JP7375088B2 - Method and system for establishing reverse flow of carotid blood flow - Google Patents

Description

REFERENCES TO RELATED APPLICATIONS This application is filed under co-pending U.S. Provisional Patent Application No. 62/145,809 entitled ``METHODS AND SYSTEMS FOR ESTABLISHING RETROGRADE CAROTID ARTERIAL BLOOD FLOW'' (filed on April 10, 2015). This provisional patent application is incorporated herein by reference in its entirety, claiming priority to the above-mentioned filing date.

BACKGROUND The present disclosure relates generally to medical methods and devices. In particular, the present disclosure relates to methods and systems for accessing carotid vessels and establishing reverse flow of blood flow during carotid stenting and other procedures.

Carotid artery disease usually consists of deposits of plaque P that narrow the junction between the common carotid artery CCA and the internal carotid artery ICA (Figure 5), the artery providing blood flow to the brain. are doing. These deposits increase the risk that embolic particles are generated and enter cerebral blood vessels, leading to neurological outcomes such as TIA, ischemic stroke, or death. neurologic consequences). Furthermore, if such stenosis becomes severe, blood flow to the brain is obstructed, with serious and often fatal consequences.

Two main treatments are used to treat carotid artery disease. The first is a surgical incision called carotid endarterectomy CEA, in which the common carotid artery, internal carotid artery, and external carotid artery are occluded, and the site of the disease (usually the common carotid artery CCA) is occluded. The carotid artery is incised at the carotid artery bifurcation (where the carotid artery bifurcates into the internal carotid artery ICA and external carotid artery ECA), the plaque P is separated and removed, and the carotid artery is then closed. The second technique relies on placing a stent in the carotid artery, called carotid artery stenting CAS, typically at or at the bifurcation of the common carotid artery CAA to the internal carotid artery ICA. It is placed across the internal carotid artery or completely within the internal carotid artery. Typically, self-expanding stents are introduced through a percutaneous puncture of the femoral artery in the groin, up the aortic arch, and into the targeted common carotid artery CCA.

Both of these methods expose the patient to the risk of emboli being released into the cerebral blood vessels via the internal carotid artery ICA. The clinical consequences of embolus release into the external carotid artery ECA, the artery that supplies blood to facial structures, are less important. During CEA, the risk of embolic release into the internal carotid artery ICA is minimized by debridement and vigorous flushing of the artery before closing the vessel and restoring blood flow. While the arteries are incised during surgery, all carotid arteries are occluded so particles cannot enter the blood vessels.

During carotid artery stenting (CAS) procedures, additional embolic protection devices are typically used to at least partially reduce the risk of embolism. An example of such a device is a distal filter, which is deployed into the internal carotid artery distal to the stent region. The filter is intended to trap embolic particles and prevent them from passing into the brain blood vessels. However, such filtering devices have certain limitations. These filtering devices must be advanced toward the target vessel and traverse the stenosis prior to deployment, which exposes the cerebral vessels to a shower of emboli. They are not always easy to advance, deploy, and remove through narrow stenoses and/or severely angular vessels. And finally, they only filter particles larger than the filter pore size (typically 100-120 μm). In addition, these devices are unable to filter 100% of the blood flow because they are not fully opposed to the filter wall, and there is a risk that debris may slip through during filter retrieval. .

Of particular interest to the present disclosure is another method to reduce the risk of embolic release into the internal carotid artery ICA, which is used during a carotid artery stenting CAS procedure, and which incorporates the concept of reversing blood flow within the internal carotid artery ICA. A method has been proposed that utilizes this method to prevent embolic debris from entering cerebral blood vessels. Although a number of specific protocols have been described, they generally rely on sheathing the common carotid artery via the femoral artery (transfemoral access). Blood flow in the common carotid artery is typically occluded by inflating a balloon on the distal tip of the sheath. Blood flow to the external carotid artery ECA may also be occluded, typically using a balloon catheter or balloon guidewire introduced through the sheath. The sheath is then connected to a venous location or to a low pressure external receptacle to establish reverse or retrograde flow from the internal carotid artery through the sheath and away from the cerebral vessels. After such backflow is established, stenting can be performed with greatly reduced risk of emboli entering cerebral vessels.

An alternative system to simply stop blood flow in the forward direction of the ICA is to use two integrated balloons: an ECA occlusion balloon at the distal tip and a CCA occlusion balloon placed some distance apart near the ECA balloon. It consists of a carotid access sheath with a Between the two balloons there is an opening through which interventional carotid stenting devices are delivered. This system does not reverse blood flow from the ICA to the venous system, but instead blocks blood flow and uses suction to remove embolic debris before establishing forward flow within the ICA. Depends on the removal.

While such blood flow reversal or stasis protocols for performing carotid endovascular stenting and other interventional procedures hold great promise, such methods generally require multiple have required separate access and manipulation of occlusion components. Furthermore, the protocol is rather complex and requires many separate steps, the performance of which has been restricted to only the most experienced vascular surgeons, interventional radiologists, and cardiologists. Moreover, due to the dimensional limitations of femoral access, the access device itself presents very high blood flow resistance, limiting the potential for regurgitation and/or aspiration. Additionally, the requirement to occlude the external carotid artery adds risk and complexity to the procedure. Balloon catheters are used to occlude the external carotid artery when the stent has been placed across the bifurcation from the common carotid artery to the internal carotid artery, and removing it would damage the deployed stent. may be trapped inside.

None of the brain protection devices and methods described provide post-surgical protection. However, the generation of embolic particles has been measured up to 48 hours or more after stent surgery. In CEA, flushing at the end of the surgery while blocking blood flow to the internal carotid artery ICA may help reduce postoperative embolism occurrence. A similar washout step in CAS would also reduce embolic risk. Additionally, stents designed to improve the uptake of embolic particles would also reduce postoperative emboli.

Furthermore, all currently available carotid artery stenting and brain protection systems are designed for access through the femoral artery. Unfortunately, the path from the femoral artery to the common carotid artery is relatively long, has several turns that are completely angular in some patients, and often contains plaque and other disease. I'm here. The portion of the procedure that involves accessing the common carotid artery from the femoral artery is difficult and time consuming, as well as showering embolic debris up both the target and opposing common carotid arteries and from there into the cerebral vessels. There is a possibility of risks arising. Several studies suggest that half or more of the embolic complications during CAS surgery occur during access to the CCA. Neither the protocol nor the system provides protection during this part of the surgery.

Recently, a reflux protocol with an alternative access route to the carotid artery was proposed by Criado. This alternative route consists of direct surgical access to the common carotid artery CCA and is referred to as transcervical or transcarotid access. Transcervical access greatly reduces the length and tortuosity of the path from the vascular access point to the target treatment site, thereby reducing the time and difficulty of the procedure. Additionally, this access route reduces the risk of embolization from navigation of diseased, angular, or tortuous aortic arch or common carotid artery anatomy.

The Criado protocol is described in several publications in the medical literature cited below. As shown in FIG. 3, the Criado protocol uses a flow shunt that includes an arterial sheath 210 and a venous sheath 212. Each sheath has a side arm 214 and terminates in a stopcock 216. The two sheath plugs are connected by connector tube 218, thereby completing a backflow shunt from arterial sheath 210 to venous sheath 212. The arterial sheath is placed into the common carotid artery CCA through a surgical incision made in the neck inferior to the carotid artery bifurcation. Occlusion of the common carotid artery CCA can be accomplished using temporary vessel ligation, such as a Rummel tourniquet and umbilical tape, or a vessel loop. A venous return sheath 212 is also placed into the internal jugular vein IJV (FIG. 3) through an open surgical incision. Backflow from the internal carotid artery ICA and external carotid artery ECA will then be established by opening the plug 216. The Criado protocol is an advance over earlier reflux protocols because it does not require femoral access. In this way, potential complications associated with femoral access are completely avoided. Furthermore, the low flow restrictions provided by the short access route provide the opportunity for vigorous reverse flow rates, increasing embolic debris removal efficiency. These reduced blood flow restrictions would allow the establishment of the desired backflow of the internal carotid artery ICA without occlusion of the external carotid artery ECA as required in the initial protocol.

Although significantly improved compared to femoral access-based regurgitation protocols, the Criado protocol and blood flow shunts could still benefit from advances. In particular, existing arterial and venous sheaths used during surgery still have significant blood flow restrictions in the side arms 214 and plugs 216. Reverse flow circuit resistance is at a maximum when the interventional catheter is inserted into the arterial access sheath. In a percentage of patients, the perfusion pressure of the external carotid artery ECA is greater than the perfusion pressure of the internal carotid artery ICA. In these patients, this pressure differential may drive antegrade blood flow from the ECA to the ICA. A reflux shunt with low blood flow resistance was able to ensure reflux in both the ECA and ICA despite the pressure gradient from the ECA to the ICA.

Furthermore, there is no means to monitor or adjust the rate of backflow. The ability to increase and/or adjust blood flow velocity sets the optimal regurgitation rate for patient tolerance and physiology and surgical stage, thereby providing advanced protection from embolic debris. will give the user the ability to Additionally, the system described by Criado relies on manually turning one or more bungs to open and close the backflow shunt, e.g., while injecting the contrast agent to facilitate installation of the CAS system. are doing. Finally, the Criado protocol relies on occlusion of a surgical incision in the common carotid artery via a vascular loop or a Rummel tourniquet. A system with means for endovascularly occluding the common carotid artery (e.g., with an occlusion element on the arterial access sheath) would allow the entire procedure to be performed using percutaneous techniques. Dew. Percutaneous approaches not only allow non-surgeons to perform the procedure, but also limit the size of the surgical incision and its associated complications.

For these reasons, transcervical access, reflux, and flushing are recommended to reduce the risk of surgical and postoperative embolization, improve the level of hemostasis throughout the procedure, and improve the ease and speed of carotid stenting. It would be desirable to provide improved methods, devices and systems for performing the procedure and for inserting carotid stents into carotid vessels. The method, device and system will simplify the procedure performed by the physician while reducing the risk of performing an inappropriate procedure and/or not achieving sufficient regurgitation and flushing to protect against embolic release. This system would provide individual devices and components that are easy to use together and prevent embolization-related complications. The method and system also provide a convenient and convenient automatic closure for some or all arterial penetrations to prevent unintended blood loss at the end of the procedure. Dew. Additionally, the systems, devices and methods may be suitable for implementation through either surgical incisions or percutaneous endovascular access routes. Additionally, the method, device, and system will allow insertion of intravascular prosthetic implants that will reduce post-operative complications. At least some of these objects will be achieved by the invention described herein below.

The disclosed methods, devices and systems establish and facilitate retrograde flow of blood circulation within the region of the carotid artery bifurcation to limit or prevent the release of emboli into cerebral vessels, particularly into the internal carotid artery. do. This method is particularly useful for interventional procedures performed within the common carotid artery through a transcervical approach or transfemorally, such as stenting and angioplasty, atherectomy, and the modified Seldinger technique. Either open surgical or percutaneous techniques are used, such as a modified Seldinger technique or a micropuncture technique.

Access to the common carotid artery (Figure 5) is established by placing a sheath or other tubular access cannula into the lumen of the artery, typically connecting the common carotid artery to the internal and external carotid arteries. The distal end of the sheath is located near the section or bifurcation B (FIG. 5). The sheath may have an occlusion member (eg, a compliant occlusion balloon) at the distal end. A catheter or guidewire with an occlusion member, such as a balloon, may be placed through the access sheath and placed proximal to the external carotid artery ECA to inhibit entry of emboli, but typically Occlusion of the external carotid artery is not required. A second return sheath is placed in the venous system (eg, internal jugular vein IJV or femoral vein FV). An arterial access sheath and a venous return sheath are connected to form an external arterial-venous shunt.

Reflux is established and adjusted to meet the patient's needs. Blood flow through the common carotid artery is occluded either by external vascular loops or tape, vascular clamps, internal occluding members such as balloons, or other types of occluding means. When blood flow through the common carotid artery is blocked, the natural pressure gradient between the internal carotid artery and the venous system forces blood flow in the opposite direction from the cerebral vessels, through the internal carotid artery, through the shunt, and into the venous system. will bring.

Alternatively, the venous sheath can be eliminated and the arterial sheath connected to an external collection reservoir or receptacle. Backflow blood can be collected into this receptacle. If necessary, the collected blood can be filtered and returned to the patient during or at the end of surgery. The pressure in the receptacle can accept atmospheric pressure to create a pressure gradient that causes blood flow in the opposite direction from the cerebral blood vessels to the receptacle, or the pressure in the receptacle can be negative.

Optionally, a balloon or other occlusion element is typically placed in the external carotid artery just above (i.e., distal to) its bifurcation with the internal carotid artery to achieve or enhance retrograde flow from the internal carotid artery. Deployment may block blood flow from the external carotid artery.

Although the procedures and protocols described below are specifically directed to carotid artery stenting, the carotid artery access methods described herein are intended to be used within the carotid system, particularly between the internal and external carotid arteries. It will also be recognized that it is useful in angioplasty, atherectomy, and other interventional procedures performed close to the bifurcation. Furthermore, it is well understood that some of these access, vascular occlusion, and embolic prevention methods are applicable to other vascular interventional procedures (e.g., acute stroke treatment). Dew.

The present disclosure includes many specific aspects for improving the performance of carotid artery access protocols. At least most of these individual aspects and improvements can be made individually or in combination with one or more other improvements to facilitate and enhance performance of certain interventions to the carotid system.

In one aspect, a system for use in carotid artery access and treatment is disclosed. The system includes an arterial access device suitable for introduction into and receiving blood flow from the common carotid artery and a shunt fluidly connected to the arterial access device. ) a shunt that provides a path for blood flow from the arterial access device to a return site; a flow control assembly suitable for regulating blood flow between two second blood flow states, the flow control assembly comprising one or more flow control assemblies that interact with the blood flow through the shunt; a blood flow control assembly including components.

In another aspect, a system for use in carotid artery access and treatment is disclosed. The system includes an arterial access device suitable for introduction into a common carotid artery to receive blood flow from the common carotid artery, and a shunt fluidly connected to the arterial access device at a return site from the arterial access device. a shunt coupled to the shunt to provide a path for blood flow to the shunt and to provide a path for blood flow through the shunt between a first blood flow rate and a second blood flow rate; a flow mechanism suitable for changing the flow rate of the first blood flow and the flow rate of the second blood flow through the shunt, automatically interacting with the flow mechanism without requiring any input from the user. and a controller that adjusts the blood flow between the flow rate and the flow rate.

In yet another aspect, a device for use in carotid artery access and treatment is disclosed. The device includes a distal sheath having a distal end, a proximal end, and a lumen extending between the distal and proximal ends suitable for introduction into the common carotid artery; a proximal extension having an end, a proximal end, and a lumen therebetween, the distal end of the proximal extension having a contiguous lumen at a junction; ) a proximal extension connected to the proximal end of the sheath, and a flow line having a lumen, the blood flowing into the distal end of the sheath from a blood flow line connected near the junction and a hemostasis valve at the proximal end of the proximal extension to allow flow into the distal sheath through the proximal extension; a hemostatic valve suitable for restricting blood flow from the proximal extension while allowing catheterization of the proximal extension.

In another aspect, a method of accessing and treating a carotid artery is disclosed. This method includes the steps of forming a penetration in the wall of the common carotid artery, positioning an access sheath through the penetration, blocking blood flow from the common carotid artery through which the sheath has passed, and removing the sheath from the carotid artery. and allowing blood flow to flow back from the sheath to the return site via a flow path, and modifying the blood flow through the flow path based on the feedback data. include.

In another aspect, a method of accessing and treating a carotid artery is disclosed. The method includes the steps of forming a penetration in the wall of the common carotid artery, positioning an access sheath through the penetration, blocking blood flow from the common carotid artery through which the sheath has passed, and allowing blood flow to flow back from the sheath through the blood flow path to the return site; and monitoring blood flow through the blood flow path.

In another aspect, a method of accessing and treating a carotid artery is disclosed. The method includes the steps of forming a penetration in the common carotid artery wall, positioning an arterial access sheath through the penetration, blocking blood flow from the common carotid artery through which the sheath has passed, and The method includes the steps of allowing blood flow to flow back from the internal carotid artery into the sheath while the carotid artery remains occluded, and adjusting the conditions of blood flow back through the sheath.

In another aspect, a method of accessing and treating a carotid artery is disclosed. This method includes the steps of forming a penetration in the common carotid artery wall, positioning an arterial access sheath through the penetration, blocking blood flow from the common carotid artery through which the sheath has passed, and blocking the common carotid artery. and adjusting the rate of blood flow back from the sheath to a level tolerated by the patient, the method comprising: and adjusting the speed, the speed being a baseline.

This application is based on U.S. Pat. entitled "Methods and Systems for Establishing Retrograde Carotid Arterial Blood Flow," both of which are incorporated herein by reference.

Other features and advantages will become apparent from the following description of various embodiments illustrated for purposes of illustration and principles of the invention.

FIG. 1A is a schematic diagram of a counterflow blood flow system including a blood flow control assembly, an arterial access device accessing the common carotid artery via a transcervical approach, and a venous return device communicating with the internal jugular vein.

FIG. 1B is a schematic diagram of a retrograde blood flow system in which an arterial access device accesses the common carotid artery via a transcervical approach and a venous return device communicates with the femoral vein.

FIG. 1C is a schematic diagram of a retrograde blood flow system in which an arterial access device accesses the common carotid artery via a transfemoral approach and a venous return device communicates with the femoral vein.

FIG. 1D is a schematic diagram of a retrograde blood flow system where the retrograde flow is collected in an external receptacle.

FIG. 1E is a schematic diagram of an alternative counterflow blood flow system in which an arterial access device accesses the common carotid artery via a transcervical approach and a venous return device communicates with the femoral vein.

FIG. 2A is an enlarged view of the carotid artery, with the carotid artery occluded by an occlusion element on the sheath and connected to a backflow shunt, and an interventional device (such as a stent delivery system or other working catheter) connected to an arterial access device. into the carotid artery.

FIG. 2B shows an alternative system in which the carotid artery is occluded by a separate external occlusion device and connected to a backflow shunt, and an interventional device (such as a stent delivery system or other working catheter) is accessed through an arterial access device to the carotid artery. be introduced.

FIG. 2C is an alternative system in which the carotid artery is connected to a retrograde shunt, an interventional device (such as a stent delivery system or other working catheter) is introduced into the carotid artery via an arterial access device, and the carotid artery is connected to a separate occlusion device. Obstructed.

Figure 2D shows an alternative system in which the carotid artery is occluded, the artery is connected to a retrograde shunt via an arterial access device, and an interventional device (such as a stent delivery system) is introduced into the carotid artery via a separate arterial introducer device. be done.

Figure 3 shows the conventional Criado blood flow shunt system.

Figure 4 shows a diagram of normal cerebral circulation, including the circle of Willis.

Figure 5 shows the blood vessels in the patient's neck, including the common carotid artery CCA, internal carotid artery ICA, external carotid artery ECA, and internal jugular vein IJV.

FIG. 6A illustrates an arterial access device useful in the methods and systems disclosed herein.

FIG. 6B shows an additional arterial access device structure with a reduced diameter distal end.

7A and 7B illustrate tubes useful in the sheath of FIG. 6A.

FIG. 7C shows an embodiment of a sheath stopper.

Figure 7D shows the sheath stopper of Figure 7C attached to the sheath.

Figures 7E and 7F show the flexible sheath stopper in use.

FIG. 7G shows an embodiment of a sheath with a flexible distal portion and a sheath stopper in use.

FIG. 8A shows an additional arterial access device structure with an expandable occlusion element.

FIG. 8B shows an additional arterial access device structure with an expandable occlusion element and a reduced diameter distal end.

9A and 9B illustrate additional embodiments of arterial access devices.

9C and 9D show embodiments of valves on arterial access devices.

10A-10D illustrate embodiments of venous return devices useful in the methods and systems disclosed herein.

FIG. 11 shows the system of FIG. 1 including a blood flow control assembly.

12A-12B illustrate embodiments of variable flow resistance components useful in the methods and systems disclosed herein.

13A-13C illustrate an embodiment of a blood flow control assembly within a single housing.

14A-14E illustrate typical blood flow paths during a procedure for inserting a stent into a carotid artery bifurcation according to the principles disclosed herein.

Figures 15A-15D show typical kit and package configurations.

DETAILED DESCRIPTION FIG. 1A shows a first embodiment of a reflux system 100, which is used in the region of the carotid bifurcation to limit or prevent the release of emboli into the cerebral vessels (particularly the internal carotid artery). Suitable for establishing and facilitating reverse flow of blood circulation within the body. The system 100 interacts with the carotid artery to direct backflow from the carotid artery to a venous return site, such as the internal jugular vein (or another return site, such as another vena cava or an external receptacle in an alternative embodiment). provide. Reflux system 100 includes an arterial access device 110, a venous return device 115, and a shunt 120 that provides a reverse flow path from arterial access device 110 to venous return device 115. Flow control assembly 125 interacts with shunt 120. As described in more detail below, blood flow control assembly 125 is suitable for regulating and/or monitoring regurgitation from the common carotid artery to the internal jugular vein. Flow control assembly 125 interacts with the blood flow path via shunt 120, the internal blood flow path, and/or the external blood flow path. As described in more detail below, arterial access device 110 is inserted at least partially into the common carotid artery CCA and venous return device 115 is inserted at least partially into a venous return site, such as an internal jugular vein IJV. Ru. Arterial access device 110 and venous return device 115 are coupled to shunt 120 at coupling locations 127a, 127b. When blood flow through the common carotid artery is blocked, the natural pressure gradient between the internal carotid artery and the venous system causes blood to flow in the reverse direction RG ( Figure 2A). Blood flow control assembly 125 regulates, augments, assists, monitors, and/or otherwise regulates retrograde blood flow.

In the embodiment of FIG. 1A, arterial access device 110 accesses the common carotid artery CCA via a transcervical approach. Transcervical access provides a short and tortuous route from the vascular access point to the target treatment site, thereby reducing the time and difficulty of the procedure compared to, for example, a transfemoral approach. do. In certain embodiments, the arterial distance from the arteriotomy to the target treatment site (as measured by the distance traveled through the artery) is 15 cm or less. In some embodiments, the distance is between 5 and 10 cm. Additionally, this access route reduces the risk of embolization from pathing through diseased, angular, or tortuous aortic arch or common carotid tissue. At least a portion of the venous return device 115 is placed in the internal jugular vein IJV. In certain embodiments, transcervical access to the common carotid artery is achieved percutaneously through an incision or puncture in the skin through which the arterial access device 110 is inserted. If an incision is used, the length of the incision can be approximately 0.5 cm. An occlusion element 129, such as an expandable balloon, can be used to occlude the common carotid artery CCA at a location proximal to the distal end of the arterial access device 110. Occlusion element 129 can be placed on arterial access device 110 or can be placed on a separate device. In an alternative embodiment, the arterial access device 110 accesses the common carotid artery CCA via a direct surgical transcervical approach. In a surgical approach, the common carotid artery can be occluded using a tourniquet 2105. The tourniquet 2105 is illustrated as a phantom to indicate that it is a device used in any surgical approach.

In another embodiment shown in FIG. 1B, the arterial access device 110 accesses the common carotid artery CCA via a transcervical approach, while the venous return device 115 accesses the common carotid artery CCA via a transjugular approach, while the venous return device 115 accesses the common carotid artery CCA via a venous return site other than the jugular vein, such as the femoral vein. (e.g., a venous return site configured from the FV). The venous return device 115 can be inserted into a central vein, such as the femoral vein FV, via a percutaneous puncture in the groin.

According to another embodiment shown in FIG. 1C, the arterial access device 110 accesses the common carotid artery via a femoral approach. According to the femoral approach, the arterial access device 110 approaches the CCA, e.g., via percutaneous puncture of the femoral artery FA in the groin, up the aortic arch AA to the targeted common carotid artery CCA. . Venous return device 115 can communicate with jugular vein JV or femoral vein FV.

FIG. 1D shows yet another embodiment in which the system provides retrograde flow from the carotid artery to an external receptacle 130 (rather than a venous return site). Arterial access device 110 connects to receptacle 130 via shunt 120, which communicates with blood flow control assembly 125. The blood that has flowed back is collected into the receptacle 130. If necessary, the blood can be filtered and then returned to the patient. The pressure in receptacle 130 may be set to zero pressure (atmospheric pressure) or less, thereby providing reverse flow of blood from the cerebral vessels to receptacle 130. Optionally, to achieve or enhance retrograde flow from the internal carotid artery, typically by deploying a balloon or other occlusion element in the external carotid artery, just above its bifurcation with the internal carotid artery. Blood flow from the area may be blocked. Although FIG. 1D shows the arterial access device 110 arranged in the CCA in a transcervical approach, it is recognized that an external receptacle 130 can also be used with the arterial access device 110 in a transfemoral approach. Should.

FIG. 1E shows yet another embodiment of a reflux system 100. Similar to previous embodiments, the system includes an arterial access device 110, a shunt 120 with a blood flow control assembly 125, and a venous return device 115. Arterial access device 110 and venous return device 115 couple with shunt 120 at coupling locations 127a and 127b. In this embodiment, the flow control assembly also includes an in-line filter, a one-way valve, and a flow control actuator contained within a single flow control housing.

As described in detail below with respect to the enlarged view of the carotid artery in FIG. 2A, an interventional device such as a stent delivery system 135 or other working catheter can be introduced into the carotid artery via the arterial access device 110. Stent delivery system 135 can be used to treat plaque P, such as deploying a stent within the carotid artery. The arrow RG in FIG. 2A represents the direction of reverse flow.

FIG. 2B shows another embodiment in which the arterial access device 110 is used not only to introduce at least one interventional device into the carotid artery, but also to form an arterial-to-venous shunt. used. A separate arterial occlusion device 112 with an occlusion element 129 can be used to occlude the common carotid artery CCA at a location proximal to the distal end of the arterial access device 110.

FIG. 2C shows yet another embodiment in which the arterial access device 110 is used to not only occlude an artery using an occluding element 129, but also to form an arterial-venous shunt. A separate arterial introducer device can be used to introduce at least one interventional device into the carotid artery at a location distal to the arterial access device 110.

Organizational Description Collateral Brain Circulation
The circle of Willis CW is the main arterial anastomosis of the brain, connecting all the major arteries supplying the brain, namely the two internal carotid arteries (ICAs) and the vertebrobasilar system. . Blood is carried from the circle of Willis to the brain by the anterior, middle, and posterior cerebral arteries. This communication between arteries can form collateral circulation through the brain. It provides a safety mechanism in the event of blockage of one or more of the blood vessels supplying blood to the brain, as blood flow can take an alternative route. Even if there is a blockage somewhere in the arterial system (e.g., when the ICA is ligated as described herein), the brain will most likely continue to receive an adequate blood supply. can. Blood flow through the circle of Willis ensures adequate cerebral blood flow through multiple pathways that redistribute blood to the blood-deprived side.

The collateral potential of the circle of Willis is thought to depend on the presence and size of its constituent vessels. It should be recognized that considerable anatomical variation between individuals may exist in these vessels and that many of the vessels involved may be diseased. For example, some people are missing one of their transportation arteries. When initiating blockade in such people, the collateral circulation is at risk of resulting in an ischemic event and potential brain damage. Additionally, autoregulatory responses to decreased perfusion pressure may include dilation of collateral arteries (eg, communicating arteries) within the circle of Willis. This compensation mechanism sometimes requires an adjustment period before collateral circulation reaches a level that supports normal function. This autoregulatory response can occur over a period of 15-30 seconds and can only compensate for pressure and blood flow reductions within a certain range. Therefore, a transient ischemic attack may occur during the adjustment period. Very high reflux rates over a long period of time can cause a situation where the patient's brain is not getting enough blood flow and the patient may experience neurological symptoms or, in some cases, transient ischemic attacks. may cause a situation where you cannot

Figure 4 shows normal cerebral circulation and organization of the circle of Willis CW. The aorta AO gives rise to the innominate artery BCA, which bifurcates into the left common carotid artery LCCA and left subclavian artery LSCA. Aortic AO further gives rise to right common carotid artery RCCA and right subclavian artery RSCA. The left and right common carotid arteries CCA give rise to the internal carotid artery ICA, which branches into the middle cerebral artery MCA, the posterior communicating artery PcoA, and the anterior cerebral artery ACA. The anterior cerebral artery ACA supplies blood to the frontal lobe and some parts of the striatum. The middle cerebral artery MCA is an aorta with dendritic branches that supply blood throughout the lateral aspect of each hemisphere of the brain. The left and right posterior cerebral arteries PCA arise from the basilar artery BA and supply blood to the back of the brain (occipital lobe).

Anteriorly, the circle of Willis is formed by the anterior cerebral artery ACA and the anterior communicating artery ACoA, which connects the two ACAs. The two posterior communicating arteries PCoA connect the circle of Willis to the two posterior cerebral arteries PCA, which branch from the basilar artery BA and complete the posterior part of the circle.

The common carotid artery CCA also gives rise to the external carotid artery ECA, which branches extensively to supply most structures of the head except the brain and contents of the orbit. ECA also helps supply the cervical and facial structures.

Carotid Artery Bifurcation
FIG. 5 shows an enlarged view of the relevant blood vessels in the patient's neck. At bifurcation B, the common carotid artery CCA branches into the internal carotid artery ICA and the external carotid artery ECA. The bifurcation is located approximately at the level of the fourth cervical vertebra. FIG. 5 shows a plaque P generated at the bifurcation B.

As mentioned above, the arterial access device 110 can access the common carotid artery CCA via a transcervical approach. According to a transcervical approach, the arterial access device 110 is inserted into the common carotid artery CCA at an arterial access location L, which may be, for example, a surgical incision or puncture in the wall of the common carotid artery CCA. There is a distance D between the arterial access location L and the bifurcation B, typically about 5-7 cm. When the arterial access device 110 is inserted into the common carotid artery CCA, it is undesirable for the distal tip of the arterial access device 110 to come into contact with the bifurcation B, which could shatter the plaque P and cause the generation of embolic particles. may bring. To minimize the possibility of arterial access device 110 contacting bifurcation B, in some embodiments, only about 2 to 4 cm of the distal region of the arterial access device is inserted into the common carotid artery CCA during the procedure. Ru.

The common carotid artery is surrounded on each side by a layer of fascia called the carotid sheath. The carotid sheath also encloses the internal jugular vein and vagus nerve. The anterior side of the carotid sheath is the sternocleidomastoid muscle. Percutaneous or surgical transcervical access to the common carotid artery and internal jugular vein is made from just above the clavicle through the carotid sheath between the two heads of the sternocleidomastoid muscle, avoiding the vagus nerve. It is done with care.

At the upper end of this carotid sheath, the common carotid artery bifurcates into the internal and external carotid arteries. The internal carotid artery continues to ascend without branching until it enters the cranium and supplies blood to the retina and brain. The external carotid artery branches to supply blood to the scalp, face, eyes, and other superficial structures. Several facial and cranial nerves are intertwined both anteriorly and posteriorly with the artery. Additional cervical muscles may also cover the bifurcation. During a carotid endarterectomy procedure, these neural and muscular structures can be dissected and pushed aside to access the carotid artery bifurcation. In some cases, the carotid artery bifurcation is closer to the level of the mandible, where access is more challenging and there is less room to be able to separate it from the various nerves that are spared. In these cases, open endarterectomy procedures may not be the preferred choice, as the risk of inadvertent nerve injury may be increased.

Reverse Flow System Details As previously mentioned, the reverse flow system 100 provides an arterial access device 110, a venous return device 115, and a pathway for reverse flow from the arterial access device 110 to the venous return device 115. Contains a shunt 120. The system also includes a blood flow control assembly 125 that interacts with the shunt 120 to regulate and/or monitor blood flow back through the shunt 120. Exemplary embodiments of the components of reflux system 100 are described herein.

Arterial Access Device FIG. 6A shows an exemplary embodiment of an arterial access device 110, including a distal sheath 605, a proximal extension 610, a blood flow line 615, an adapter or Y connector 620, and a hemostatic valve 625. . The arterial access device also includes a dilator 645 with a tapered tip 650 and an introducer guidewire 611. Arterial access devices comprising dilators and introducer guidewires are used together to increase access to blood vessels. A feature of arterial access devices is that they can be optimized for transcervical access. For example, the placement of the components of the access device can be modified to limit potential damage to the blood vessel through sharp insertion angles, to allow atraumatic and safe insertion of the sheath, and to insert sheaths, sheath dilators, etc. into the blood vessel. and can be optimized to limit the length of the introducer guidewire.

The distal sheath 605 is suitable for being introduced through an incision or puncture into the wall of the common carotid artery, either by an open surgical incision or by a percutaneous puncture established using, for example, the Seldinger technique. There is. The length of the sheath can range from 5 to 15 cm, typically 10 to 12 cm. The inner diameter typically ranges from 7Fr to 10Fr (French: 1Fr=0.33mm), usually 8Fr. In particular, when the sheath is introduced via a transcervical approach above the clavicle but below the bifurcation of the carotid artery, the sheath 605 has hoop strength to resist kinking and backling. It is desirable to be very flexible while maintaining strength. In this manner, the distal sheath 605 may be reinforced from the periphery by braid, helical ribbon, helical wire, cut tubing, etc. An inner liner may be included such that the reinforcing structure is sandwiched between the outer jacket layer and the inner liner. The inner liner may be a low friction material such as PTFE. The outer coating may be one or more of a group of materials including Pebax, thermoplastic polyurethane, or nylon. In some embodiments, the reinforcing structure or material and/or the outer covering material or thickness may vary over the length of the sheath 605 to vary the flexibility along the length. In an alternative embodiment, the distal sheath is suitable for introduction up the aortic arch AA and into the targeted common carotid artery CCA, for example via percutaneous puncture of the femoral artery in the groin.

As shown in FIG. 6B (showing an enlarged view of the distal region 630 of the sheath 605), the distal sheath 605 has a stepped or other shape having a reduced diameter distal region 630. It can have a form. The distal region 630 of the sheath is sized for insertion into a carotid artery, with an internal diameter typically ranging from 0.085 inches to 0.115 inches. , the remaining proximal region of the sheath has larger outer and inner diameters, typically between 2.794 mm (0.110 inch) and 3.43 mm (0.135 mm). inches). The larger lumen diameter in the proximal region minimizes the overall blood flow resistance of the sheath. In some embodiments, the length of the reduced diameter distal portion 630 is approximately 2 cm to 4 cm. The relatively short length of the reduced diameter distal portion 630 allows this portion to be located in the common carotid artery CCA via a transcervical approach while reducing the risk of the distal end of the sheath 605 coming into contact with bifurcation B. make it possible. Additionally, the reduced diameter distal portion 630 also allows for reducing the size of the dissected artery for introducing the sheath 605 into the artery, with only a minor effect on the level of blood flow resistance. Additionally, the reduced diameter distal portion may be more flexible and therefore more conformal to the lumen of the blood vessel.

Referring again to FIG. 6A, the elongated body proximal extension 610 has a lumen contiguous with the lumen of the sheath 605. The lumens can be connected by a Y connector 620 that also connects the lumen of blood flow line 615 to the sheath. In the assembly system, blood flow line 615 is connected to and forms a first leg of backflow shunt 120 (FIG. 1). Proximal extension 610 can have a length sufficient to space hemostasis valve 625 from Y-connector 620, which is adjacent to a percutaneous or surgical insertion site. By spacing the hemostasis valve 625 away from the percutaneous insertion site, the physician can place the stent delivery system or other working catheter within the fluoroscopic field of view when fluoroscopy is being performed. It can be introduced into proximal extension 610 and sheath 605 while remaining outside. In certain embodiments, the proximal extension is approximately 16.9 cm from the most distal junction with the sheath 605 (such as the hemostasis valve) to the proximal end of the proximal extension. In certain embodiments, the proximal extension has an inner diameter of 0.125 inches and an outer diameter of 0.175 inches. In certain embodiments, the proximal extension has a wall thickness of 0.025 inches. For example, the inner diameter may range from 0.60 inch to 0.150 inch, with a wall thickness of 0.010 inch to 0.050 inch. In another embodiment, for example, the inner diameter may range from 0.150 inch to 0.250 inch, with a wall thickness of 0.025 inch to 0.100 inch. The dimensions of the proximal extension may vary. In certain embodiments, the proximal extension has a length within the range of about 12-20 cm. In another embodiment, the proximal extension has a length within the range of about 20-30 cm.

In certain embodiments, the distance along the sheath from hemostasis valve 625 to the distal tip of sheath 605 ranges from about 25 to 40 cm. In certain embodiments, the distance is in the range of about 30-35 cm. With the introduction of a 2.5 cm sheath into the artery and the configuration of the system to allow for a 5 to 10 cm arterial distance from the dissected arterial site to the target site, this system can accommodate a 32 to 43 cm hemostasis valve625. (the site of introduction of the interventional device into the access sheath) to the target site, which allows for a distance of approximately 32.5 cm to 42.5 cm. This distance is approximately one third of the distance required by the prior art.

A flush line 635 can be connected to the hemostatic valve 625 side and can have a plug 640 at its proximal or distal end. Flush line 635 allows for the introduction of saline, contrast fluid, etc. during surgery. Flush line 635 will also allow pressure to be monitored during surgery. A dilator 645 can be provided with a tapered distal end 650 to facilitate introduction of the distal sheath 605 into the common carotid artery. As best seen in FIG. 7A, dilator 645 can be introduced through hemostatic valve 625 such that tapered distal end 650 extends through the distal end of sheath 605. Dilator 645 can have a central lumen to accommodate a guidewire. Typically, a guidewire is first placed in the blood vessel and a dilator/sheath combination is moved over the guidewire and introduced into the blood vessel.

Also shown in FIG. 7A, a sheath stopper 705, such as in the form of a tube, may optionally be provided, which is coaxially received on the outside of the distal sheath 605. Sheath stopper 705 is designed to act as a sheath stopper to prevent the sheath from being inserted too far into the blood vessel. Sheath stopper 705 is sized and shaped to be placed on sheath body 605 so as to cover a portion of sheath body 605 and leave a distal portion of sheath body 605 exposed. Tube 705 may have a flared proximal end 710 for engaging adapter 620, and a distal end 715. Optionally, the distal end 715 may be beveled, as shown in FIG. 7B. Sheath stopper 705 may serve at least two purposes. First, as shown in FIG. 7A, the length of the sheath stopper 705 limits the introduction of the sheath 605 to the exposed distal portion of the sheath 605, which limits the length of the sheath to be inserted to the exposed distal portion of the sheath. limited to the digits. In certain embodiments, the sheath stopper limits the exposed distal portion to a range of 2-3 cm. In certain embodiments, the sheath stopper limits the exposed distal portion to 2.5 cm. In other words, the sheath stopper may limit insertion of the sheath into the artery to a range of about 2-3 cm or 2.5 cm. Second, the tube 705 can engage a pre-deployed puncture closure device that is placed in the carotid artery wall and withdraw the sheath 605 without removing the closure device, if present. make it possible. The sheath stopper 705 may be made of a transparent material so that the sheath body beneath the sheath stopper 705 is clearly visible. The sheath stopper 705 may also be made of a flexible material, or the sheath stopper 705 may be made of flexible material to allow the sheath to bend depending on the proper position when inserted into the artery. It may also include additional articulating or portions. For example, the distal portion of the sheath stopper may be made of a harder material and the proximal portion may be made of a more flexible material. In certain embodiments, the harder material has a durometer of 85A and the more flexible portion has a durometer of 50A. In some embodiments, the stiffer distal portion is 1-4 cm of the sheath stopper 705. If the user desires to insert a longer sheath, the user can remove the sheath stopper 705, cut the length (of the sheath stopper) to a shorter length, and place a The sheath stopper 705 may be removable from the sheath so that the sheath stopper 705 can be reassembled at any time.

FIG. 7C shows another embodiment of a sheath stopper 705 adjacent a sheath 605 with a dilator 645 disposed therein. The sheath stopper 705 of FIG. 7C may be deformed from a first shape to a second shape different from the first shape, such as a straight shape, and the sheath stopper 705 may be deformed by an external force sufficient to change its shape. remains in the second configuration until it acts on the sheath stopper. The second shape may be non-straight, curved, or have other contours or irregular shapes. For example, FIG. 7C shows a sheath stopper 705 with multiple bends and straight sections. It should be appreciated that FIG. 7C merely shows an example and that the sheath stopper 705 may be shaped with any amount of curvature along the longitudinal axis. FIG. 7D shows a sheath stopper 705 placed on the sheath 605. Sheath stopper 705 is harder than sheath 605 such that sheath 605 takes a shape or contour that matches the shape of the profile of sheath stopper 705.

The sheath stopper 705 may be shaped according to the angle of insertion of the sheath into the artery and the depth of the artery or patient body shape. This feature reduces the forces of the sheath tip within the vessel wall, especially if the sheath is inserted into the vessel at a steep angle. Even if the angle of entry into the arteriotomy is relatively steep, the sheath stopper may be bent or otherwise deformed into a shape that assists in coaxially orienting the sheath with the invading artery. The sheath stopper may be molded by the operator before inserting the sheath into the patient. Alternatively, the sheath stopper may be shaped and/or reshaped in situ after the sheath is inserted into the artery. Figures 7E and 7F illustrate an example of a flexible sheath stopper in use. FIG. 7E shows a straight sheath stopper 705 placed on the sheath 605. Sheath 605 is fitted with straight sheath stopper 705 and enters artery A at a relatively steep angle such that the distal tip of sheath 605 is adjacent to or facing the wall of the artery. In FIG. 7F, the user bends sheath stopper 705 to adjust the angle of incidence of sheath 605 so that the long axis of sheath 605 is more parallel to the axis of artery A. In this manner, the sheath stopper 705 has a shape that assists in orienting the sheath 605 away from the opposite wall of the artery A, and in a direction that is more coaxial with the axis of the artery A relative to the shape of FIG. 7E. Formed by users.

In some embodiments, the sheath stopper 705 is made of a compliant material or includes a compliant composite component disposed on or within the sheath stopper. In another embodiment, the sheath stopper is configured to join using an actuator, such as a concentric tube, a pull wire, or the like. The walls of the sheath stop may be reinforced with ductile wire or ribbon to help retain its shape against external forces, for example when the sheath stop encounters bends in the artery or entryway. good. Alternatively, the sheath stopper may be constructed of a uniform, compliant tube of material including metals and polymers. The body of the sheath stopper may also be at least partially constructed of a reinforced braid or coil capable of retaining its shape after deformation.

Another sheath stopper embodiment is designed to facilitate adjustment of the position of the sheath stopper (relative to the sheath) even after the sheath has been placed within the blood vessel. One embodiment of the sheath stopper is a sheath stopper that extends along the entire length or most of the length so that the sheath stopper can be removed from the sheath body, moved forward or backward as desired, and then repositioned along the length of the sheath body. The tube includes a tube with a slit. The tube may have a tab or feature on the proximal end to allow the tube to be grasped and removed more easily.

In another embodiment, the sheath stopper is a very short tube (such as a band) or a ring present on the distal portion of the sheath body. The sheath stopper may include features that allow it to be easily grasped with forceps and pulled backwards or forwards to a new position as desired, for example, to properly set the length of sheath insertion in a procedure. The sheath stopper may be secured to the sheath body either through friction from the tubing material or through a clamp that can be opened and closed against the sheath body. The clamp may be a spring-loaded clamp, typically fixed on the sheath body. To move the sheath stopper, the user may open the clamp with his fingers or a device, adjust the position of the clamp, and then remove the clamp. Design the clamp so that it does not interfere with the sheath body.

In another embodiment, the sheath stopper includes a feature that allows the sheath stopper and sheath to be sutured to the patient's tissue, which improves sheath securement and reduces the risk of sheath dislodgement. This feature may be a suture eyelet attached or shaped within the sheath stopper tube.

In another embodiment, as shown in FIG. 9A, the sheath stopper 705 includes a distal flange 710 that distributes the force of the sheath stopper over a larger area on the vessel wall, thereby preventing vessel injury or The sheath stopper is sized and shaped to reduce the risk of accidental insertion of the sheath stopper through the dissected artery and into the blood vessel. The flange 710 may be circular or other atraumatic shape large enough to distribute the force of the sheath stopper over a larger area on the vessel wall. In some embodiments, the flange is expandable or mechanically expandable. For example, the arterial sheath and sheath stopper may be inserted into the surgical site through a small puncture in the skin and then expanded prior to insertion of the sheath into the artery.

The sheath stopper may include one or more cutouts or indents 720 along the length of the sheath stopper, such that the indentation increases the flexibility of the sheath stopper, while Creates a staggered configuration that maintains axial strength to allow forward force of the sheath stopper. The notch may be used to facilitate securing the sheath to the patient via sutures and to reduce dislodgment of the sheath. The sheath stopper may also include a connector element 730 on the proximal end corresponding to features of the arterial sheath so that the sheath stopper can be secured to or unsecured from the arterial sheath. For example, the connector element is typically a hub with an L-shaped slot 740 that corresponds to a pin 750 on the hub to create a mount-style bayonet connection. do. In this manner, the sheath stopper can be securely connected to the hub, reducing the possibility that the sheath stopper will be inadvertently removed from the hub unless it is unsecured from the hub.

The distal sheath 605 can be configured to establish a curvilinear change from a normal anterior-posterior approach on the common carotid artery to an axial direction of the normal lumen within the common carotid artery. Arterial access through the common carotid artery wall, either from direct surgical incision or percutaneous access, may typically require a larger angle of access than other arterial access sites. This is due to the fact that the common carotid artery insertion site is much closer to the treatment site (ie, carotid bifurcation) than from other access points. A larger access angle is required to increase the distance from the insertion site to the treatment site, allowing insertion of the sheath at an appropriate distance without the distal tip of the sheath reaching the carotid bifurcation. Make it. For example, the sheath insertion angle via transcervical access is typically 30-45° or even greater, whereas for femoral artery access, the sheath insertion angle may be 15-20°. Therefore, the sheath must bend more than typical with the introducer sheath, without kinking, and without creating excessive forces on the opposite artery wall. Additionally, the tip of the sheath desirably does not abut or contact the arterial wall after insertion in a manner that restricts blood flow to the sheath. The insertion angle of the sheath is defined as the angle between the axis of the lumen of the artery and the long axis of the sheath.

The sheath body 605 may be formed in a variety of ways to allow for this greater bending as required by the angle of access. For example, the sheath and/or dilator may have a combined flexible bending stiffness that is less than a typical introducer sheath. In certain embodiments, the sheath/dilator combination (i.e., the sheath with the dilator disposed within the sheath) has a flexible composite stiffness in the range of about 80 and 100 N-m ² x 10 ^-6 (E*I), where E is the elastic modulus and I is the area moment of inertia of the device. The sheath alone has a bending stiffness in the range of about 30 to 40 N-m ² x 10 ^-6 and the dilator alone has a bending stiffness in the range of about 40 to 60 N-m ² x 10 ^-6 . Typical sheath/dilator bending stiffness ranges from 150 to 250 N-m ² x 10 ^-6 . Greater flexibility can be achieved through selection of reinforcement materials or designs. For example, the sheath... 002" to .003" thickness and. It may have stainless steel ribbon coil reinforcement with a width dimension of 0.005" to .015" and an outer coating of 40 to 55D durometer hardness. In some embodiments, the coil ribbon is . 003" x .010" and the outer coating has a durometer of 45D. In some embodiments, the sheath 605 can be pre-shaped with a curve or corner at a predetermined distance (typically 0.5-1 cm) from the tip. . Pre-shaped bends or corners may typically provide turns in the range of 5° to 90°, preferably in the range of 10° to 30°. Initially, the sheath 605 will be straightened by a closure device such as a dilator 645 or other straight or shaped device placed in its lumen. After the sheath 605 has been at least partially introduced percutaneously or through other arterial wall penetrations, the obturator is withdrawn to allow the sheath 605 to resume its pre-shaped configuration within the arterial lumen. enable. The sheath may be heat set in the curved or corner shape during manufacture to retain the curved or corner shape of the sheath body after straightening during insertion. Alternatively, the reinforcing structure may be constructed of nitinol and may be heat formed into the shape of a curve or corner during manufacture. Alternatively, additional spring elements may be added to the sheath body, for example spring steel or nitinol springs may be added to the reinforcement layer of the sheath in the correct shape.

Other sheath structures include having a deflection mechanism that allows the sheath to be deployed such that the catheter can be deflected to the desired deployment angle in situ. In yet another construction, the catheter has a non-rigid configuration when placed within the lumen of the common carotid artery. After placement within the lumen, a pull wire or other stiffening mechanism can be deployed to shape or stiffen the sheath into the desired configuration. One example of such a mechanism is commonly known as "shape-lock" mechanisms, which are well described in the medical and patent literature.

Another sheath structure includes a curved dilator inserted into a straight flexible sheath, where the dilator and sheath curve during insertion. The sheath is flexible enough to conform to the tissue after the dilator is removed.

Another sheath embodiment includes one or more corner structures such that during insertion, the sheath can be bent to large angles without twisting or creating undue forces on the opposite arterial wall. A sheath including a flexible distal portion. In one embodiment, the distal-most portion of the sheath body 605 is more flexible than the remainder of the sheath body. For example, the bending stiffness of the most distal portion is between one-half and one-tenth the bending stiffness of the remainder of the sheath body 605. In certain embodiments, the most distal portion has a bending stiffness of 30 to 300 N-mm ² and the remaining portion of the sheath body 605 has a bending stiffness of 500 to 1500 N-mm ² . In a sheath configured for a CCA access site, the flexible distal-most portion includes a significant portion of the sheath body 222 that can be expressed as a ratio. In certain embodiments, the ratio of the length of the distal most flexible portion to the total length of sheath body 222 is at least one-tenth and at most one-half of the total sheath body 222 length. This change in flexibility can be achieved in a variety of ways. For example, the durometer and/or material of the outer coating in various parts may be varied. Alternatively, the reinforcing structure or material may vary along the length of the sheath body. In certain embodiments, the distal most flexible portion ranges from 1 cm to 3 cm. In certain embodiments with one or more flexible portions, the less flexible portion (relative to the most distal portion) may be 1 cm to 2 cm from the proximal portion at the most distal portion. good. In certain embodiments, the flexible distal portion has a bending stiffness in the range of about 30 to 50 N-m ² x 10 ^-6 and the less flexible portion has a bending stiffness of about 50 to 100 N-m ^{2 .} It has a bending stiffness in the range of x 10 ^-6 . In another embodiment, the more flexible portion is located 0.5 to 1.5 cm within a length of 1 to 2 cm, and the sheath enters the artery at an angle, but the distal portion of the sheath is Create an articulation that allows it to more easily parallel the axis of the vessel. These configurations containing portions of varying flexibility may be manufactured in several ways. The less flexible reinforced portions may vary, for example, with stiffer reinforcement in the proximal portion and more flexible reinforcement in the distal or articulating portion. In certain embodiments, the outermost covering material of the sheath has a durometer of 45D to 70D in the proximal portion and 80A to 25D in the distal most portion. In some embodiments, the flexibility of the sheath varies continuously along the length of the sheath body. FIG. 7G shows such a sheath inserted into an artery with a flexible distal portion that allows the sheath body to bend and its distal tip to be roughly aligned with the lumen of the blood vessel. In some embodiments, the distal portion is reinforced with more flexibility, either by varying the pitch of the coils or braids or by incorporating hypotubes cut with different cutting patterns. Made with structure. Instead, the distal portion has a different reinforcement structure than the proximal portion.

In some embodiments, the tapered tip of the distal sheath is made of a harder material than the body of the distal sheath. The purpose of this is to facilitate ease of sheath insertion by allowing for a very smooth taper on the sheath and to avoid changes in sheath tip distortion or elliptical shape during and after sheath insertion into the blood vessel. It is to reduce. In one embodiment, the distal tapered tip material is made of a harder durometer material, such as a 60-72D shore material. In another example, the distal tip is made of a separate material, such as, for example, HDPE, stainless steel or another suitable polymer or metal. In additional embodiments, the distal tip is made radiopaque, either as an addition to the polymeric material, such as tungsten or barium sulfate, or as an inherent property of the material (as is the case with most metallic materials). Manufactured from sterile materials.

In other embodiments, dilator 645 may also be of varying stiffness. For example, the tapered tip 650 of the dilator may be made of a more flexible material than the proximal portion of the dilator, which reduces the risk of vessel damage when inserting the sheath and dilator into the artery. Minimize. In certain embodiments, the flexible distal portion has a bending stiffness in the range of about 45 to 55 N-m ² x 10 ^-6 and the less flexible proximal portion has a bending stiffness of about 60 and 90 N-m ² x It has a bending stiffness in the range of 10 ^-6 . The tapered shape of the dilator may be optimized for transcervical access. For example, the length of the taper and the amount of dilator that extends past the sheath should be shorter than a typical introducer sheath to limit the amount of sheath and dilator that enters the artery. For example, the length of the taper may be 1 to 1.5 cm and extend 1.5 to 2 cm from the end of the sheath body. In certain embodiments, the dilator includes a radiopaque marker at the distal tip so that the location of the tip is easily visible under fluoroscopy.

In another embodiment, the introducer guidewire is optimally configured for transcervical access. Typically, when inserting an introducer sheath into a blood vessel, an introducer guidewire is inserted into the blood vessel first. This may be done either by micropuncture techniques or by the modified Seldinger method. There is usually a long blood vessel in the direction in which the sheath is inserted, such as into the femoral artery, into which the introducer guidewire can be inserted. In this case, the user may introduce the guide wire 10 to 15 cm or more into the blood vessel before inserting the sheath. The guidewire is designed with a flexible distal portion so as not to damage the blood vessel when introduced into the artery. The flexible section of the introducer sheath guide wire is typically 5 to 6 cm long and gradually transitions to a stiffer section. Insertion of the guidewire 10 to 15 cm means that the stiff part of the guidewire is located in the area of puncture, allowing stable assistance in the subsequent insertion of the sheath and dilator into the vessel. However, in the case of transcervical sheath insertion into the common carotid artery, there is a limit to the amount of guidewire that can be inserted into the carotid artery. In cases of carotid artery disease at the bifurcation or internal carotid artery, it is desirable to minimize the risk of embolism by inserting the wire into the external carotid artery, which means inserting only approximately 5 to 7 cm of the guide wire, or It is preferable to stop the wire before reaching the branch, which results in insertion of only 3 to 5 cm of the guide wire. Thus, a transcervical sheath guidewire may have a 3-4 cm flexible distal portion and/or a shorter transition to a stiffer portion. Alternatively, transcervical sheath guidewires have an atraumatic tip section, but a very distal and short transition to a stiffer section. For example, a softer proximal segment with a soft tip section 1.5 to 2.5 cm, followed by a transition section 3 to 5 cm long, and a stiffer proximal segment containing the remainder of the wire. continues.

In addition to the configurations described above, the introducer guidewire or micropuncture catheter or micropuncture catheter guidewire may include features that prevent inadvertent advancement of these devices into the affected portion of the carotid artery. For example, stopper features may be placed on the introducer guidewire, micropuncture catheter, and/or micropuncture guidewire to limit the insertable length of these devices. For example, the stopper feature may be a short section of tubing that can be slidably placed on the device and, once placed, stays in place on the device by friction. For example, the stopper feature may be made of a soft polymeric material such as silicone rubber, polyurethane or other thermoplastic elastomer. The stopper feature may have an inner diameter the same size as or even slightly smaller than the diameter of the device. Instead, the user must press hard on the stopper feature to unfasten the device and reposition the device, or unfasten and then unfasten or re-fasten the stopper feature on the device. Additionally, the stopper feature may be configured to be fixed on the device. Features of the stopper may be positioned for optimal insertion into the blood vessel based on the location of the puncture site, the distance of the bifurcation to the puncture site, and the amount of disease at the carotid bifurcation.

The sheath guidewire may have guide wire markings to assist the user in determining the location of the tip of the wire relative to the dilator. For example, there may be a mark on the proximal end of the wire corresponding to when the tip of the wire is just at the tip of a micro access cannula. This mark provides quick wire position feedback and helps the user limit the amount of wire inserted. In another embodiment, the wire may include additional markings and a set distance (eg, 5 cm) to alert the user that the wire is present in the cannula. Alternatively, the introducer guidewire, micropuncture catheter and/or micropuncture guidewire may be constructed of, or have portions constructed of, a material that is markable with a marking pen. , where this mark is readily visible within a cath lab or operating room (OR) environment. In this embodiment, the user pre-marks the components based on anatomical information as described above and uses these marks to determine the maximum insertion amount in each component. For example, the guidewire may have a white coating around the marked portion.

In some embodiments, the sheath has built-in puncturing capabilities and an atraumatic tip similar to the tip of a guidewire. This eliminates the need for needle and wire changes currently used in arterial access with micropuncture techniques, thus saving time, reducing blood loss, and requiring less surgical skill.

In another embodiment, the sheath dilator is configured to be inserted over a 0.018" guide wire for transcervical access. Standard sheath insertion using a micropuncture kit is performed using a 22 Ga needle. First insertion of a .018” guide wire through the tube, then using a micropuncture catheter. .035" or .038" guidewire, and finally. Requires insertion of a sheath and dilator over a .035" or .038" guidewire. There is no need for wire changes due to the presence of insertable sheaths over the 018" guide wires. ) typically have a longer dilator taper; 018” wire to the sheath body. Unfortunately, transcervical access limits the length of sheath and dilator insertion, so these existing sheaths are not suitable. Another disadvantage is that the .018'' guide wire does not provide the necessary assistance to insert the sheath at a sharper angle into the carotid artery. In embodiments disclosed herein, a transcervical sheath system includes a sheath body, a sheath dilator, and slidably fits within the sheath dilator. It includes an inner tube with a tapered distal end that can accommodate a 0.018'' guidewire.

To use this embodiment of the sheath system, . A .018" guide wire is first inserted into the vessel through a 22 Ga needle. A coaxially mounted sheath system is inserted over the .018" wire. The internal tube comes first. 018" wire, which essentially advances the .018" wire, both in outer diameter and mechanical assistance. 035" or .038" guidewire equivalent. It's at the proximal end. The sheath and dilator are then advanced over the .018" wire and internal tube into the vessel. This configuration does not require a longer dilator taper, similar to current transradial artery sheaths, and with guidewire assistance similar to standard introducer sheaths, eliminates the wire exchange step. As mentioned above, this configuration of the sheath system may include a stopper feature, which is used during sheath insertion. Prevents inadvertent over-advancement of the .018" guidewire and/or inner tube. Once the sheath is inserted, the dilator, inner tube, and .018" guidewire are removed.

FIG. 8A shows another embodiment of an arterial access device 110. This embodiment is substantially similar to the embodiment shown in FIG. 6A, except that the distal sheath 605 includes an occlusion element 129 for occluding blood flow (e.g., through the common carotid artery). . If occlusion element 129 is an inflatable structure such as a balloon, sheath 605 can include an inflation lumen in communication with occlusion element 129. The occlusion element 129 can be an inflatable balloon, such as an inflatable cuff or an outwardly skirted part that engages the inner wall of the common carotid artery and blocks blood flow therethrough. Deployable by an expanded conical or other circumferential element, a membrane-covered braid, a slotted tube that expands radially when compressed axially, or by mechanical means. A similar structure can also be used. For balloon occlusion, the balloon may be compliant, non-compliant, elastomeric, reinforced, or have various other characteristics. In some embodiments, the balloon is an elastic balloon that is closely received over the outside of the distal end of the sheath prior to inflation. When inflated, the elastic balloon can expand and conform to the internal wall of the common carotid artery. In some embodiments, the elastic balloon can expand to at least twice the diameter compared to the non-deployed configuration, often to at least three times the diameter compared to the non-deployed configuration, and more. Preferably, it is expandable to at least four times the diameter, or even more, than the undeployed configuration.

As shown in FIG. 8B, the distal sheath 605 with occlusion element 129 can have a stepped or other configuration with a reduced diameter distal region 630. The distal region 630 is sized for insertion into the carotid artery, and the remaining proximal region of the sheath 605 has a larger outer and inner diameter, typically 2.794 mm. (0.110 inch) to 3.43 mm (0.135 inch). The larger lumen diameter in the proximal region minimizes the overall blood flow resistance of the sheath. In some embodiments, the length of the reduced diameter distal portion 630 is approximately 2 cm to 4 cm. The relatively short length of the reduced diameter distal portion 630 allows this portion to be located in the common carotid artery CCA via a transcervical approach while reducing the risk of the distal end of the sheath 605 coming into contact with bifurcation B. make it possible.

FIG. 2B shows an alternative embodiment in which the occlusion element 129 can be introduced into the carotid artery on a second sheath 112 that is separate from the distal sheath 605 of the arterial access device 110. The second or "proximal" sheath 112 may be suitable for insertion into the common carotid artery in a proximal or "inferior" direction away from the cerebral vessels. As generally discussed above, the second proximal sheath may include an inflatable balloon 129 or other occlusion element. The distal sheath 605 of the arterial access device 110 can then be placed in the common carotid artery distal to the second proximal sheath and oriented distally, typically toward the cerebral vessels. Separate occlusion and access sheaths can be used to reduce the size of the dissected artery required for introduction of the access sheath.

FIG. 2C shows yet another embodiment of a two arterial sheath system, where the interventional device is introduced by a distal sheath 605 of the arterial device 110 and a separate introducer sheath 114. A second or "distal" sheath 114 may be suitable for insertion into the common carotid artery distal to the arterial access device 110. Similar to the previous embodiment, the size of each dissected artery can be reduced by using two separate access sheaths.

As can be seen in transcervical access procedures, in situations where the insertion of the sheath into the artery is at an acute angle and/or the length of the inserted sheath is short, the distal tip of the sheath may partially or completely It is more likely to be placed in contact with the vessel wall, thereby restricting blood flow to the sheath. In some embodiments, the sheath is designed to center its tip within the lumen of the blood vessel. One such embodiment includes a balloon, such as occlusion element 129 described above. In another embodiment, the balloon does not occlude blood flow and may be centered with the tip of the sheath away from the vessel wall, like an inflatable bumper. In another embodiment, the expandable feature is located at the tip of the sheath and expands mechanically once the sheath is in place. Examples of mechanically expandable features include braided or helical structures or longitudinal struts that expand radially when collapsed.

In certain embodiments, occlusion of the blood vessel proximal to the distal tip of the sheath may be made from outside the blood vessel, such as in a Rummel tourniquet or a blood vessel loop proximal to the sheath insertion site. In an alternative embodiment, the occlusion device includes a loop around the sheath tip, such as an elastic loop, an inflatable cuff, or a mechanical clamp that can be tightened around the blood vessel and the distal sheath tip. It may also fit outside the blood vessel. In systems with reverse blood flow, this method of vessel occlusion minimizes the area of quiescent blood flow, thereby lowering the risk of thrombus formation, and also ensures that the sheath tip is axially aligned with the vessel, allowing the vessel wall to Guarantees no partial or complete blockage.

In some embodiments, the distal portion of the sheath body includes a side hole so that blood flow to the sheath is maintained even if the tip of the sheath is partially or completely blocked by the arterial wall. But that's fine.

Another arterial access device is shown in FIGS. 9A-9D. This configuration has a different style of connection with the blood flow shunt than the previously described versions. FIG. 9A shows the components of arterial access device 110 including arterial access sheath 605, sheath dilator 645, sheath stopper 705 and sheath guidewire 111. FIG. 9B shows the arterial access device 110 as assembled for insertion over a sheath guidewire 611 into a carotid artery. After insertion of the sheath into the artery and during the procedure, sheath guidewire 611 and sheath dilator 705 are removed. In this configuration, the sheath has a sheath body 605, a proximal extension 610 and a hemostasis valve 625 with a flush line 635 and a bung 640. Proximal extension 610 extends from Y adapter 660 to hemostasis valve 625 to which flush line 635 connects. The sheath body 605 is a portion sized to be inserted into the carotid artery, and is actually inserted into the artery during use.

Instead of a Y-connector with a blood flow line connection that terminates within the valve, the sheath has a Y-adapter 660 that connects the distal portion of the sheath to the proximal extension 610. The Y-adapter may also include a valve 670 operable to open and close fluid connection with a connector or hub 680 to which a blood flow line, such as a shunt, can be removably connected. Valve 670 is positioned immediately adjacent to the internal lumen of adapter 660, which communicates with the internal lumen of sheath body 605. 9C and 9D show cross-sectional details of Y adapter 660 with valve 670 and hub 680. Figure 9C shows the valve closed to the connector. This is the valve placement during adjustment of the arterial sheath. The valve is configured so that there is no possibility of trapping air during adjustment of the sheath. Figure 9D shows the valve open to the connector. This arrangement is used when blood flow shunt 120 is connected to hub 680, allowing blood flow from the arterial sheath to the shunt. This configuration eliminates the need to condition both the flush line and the blood flow line and instead allows for conditioning with a single flush line 635 and bung 640. This single-point adjustment is identical to the adjustment of a traditional introducer sheath that does not have a connection to the shunt line, so the user is more familiar with it; It's more convenient. Additionally, the lack of blood flow lines on the sheath makes manipulation of the arterial sheath easier during adjustment and insertion into the artery.

Referring again to FIG. 9A, the sheath may also include a second, more distal connector 690, which is separated from the Y-adapter 660 by a section of tubing 665. The purpose of this second connector and tube 665 is to allow the valve 670 to be placed more proximally from the distal tip of the sheath while still limiting the length of the insertable portion of the sheath 605, thus When the blood flow shunt is connected to the arterial sheath during the procedure, it allows for a reduction in the level of exposure of the user to the radiation source. In some embodiments, the distal connector 690 includes suture eyelets to help secure the sheath to the patient after deployment.

Venous Return Device Referring now to FIG. 10, the venous return device 115 can include a distal sheath 910 and a blood flow line 915 and is connected to the shunt 120 to form the legs of the shunt 120 during use of the system. do. The distal sheath 910 is suitable for introduction into a venous return location (such as a jugular or femoral vein) through an incision or puncture. Distal sheath 910 and blood flow line 915 can be permanently attached, or can be attached using a conventional luer fitting, as shown in FIG. 10A. Optionally, the sheath 910 can be coupled to a blood flow line 915 by a Y connector 1005, as shown in FIG. 10B. Y connector 1005 may include a hemostatic valve 1010. The venous return device also includes a venous sheath dilator 1015 and an introducer guide wire 611 that facilitate introduction of the venous return device into the internal jugular vein or other vein. Similar to arterial access dilator 645, venous dilator 1015 includes a guidewire central lumen so that a venous sheath and dilator combination can be placed over guidewire 611. Optionally, the venous sheath 910 can include a flush line 1020 with a plug 1025 at the proximal or distal end.

An alternative configuration is shown in FIGS. 10C and 10D. FIG. 10C shows the components of venous return device 115, including venous return sheath 910, sheath dilator 1015, and sheath guidewire 611. FIG. 10D shows venous return device 115 as assembled for insertion over sheath guidewire 611 into a central vein. Once the sheath is inserted into the vein, the dilator and guide wire are removed. The venous sheath may include a hemostatic valve 1010 and a blood flow line 915. A plug 1025 at the blood flow end allows flushing of the venous sheath through the blood flow line before use. This configuration allows the sheath to be adjusted from a single point, similar to traditional introducer sheaths. A connection for blood flow shunt 120 is made with connector 1030 on bung 1025.

To reduce overall system blood flow resistance, arterial access blood flow line 615 (FIG. 6A) and venous return blood flow line 915, as well as Y connectors 620 (FIG. 6A) and 1005, each have relatively large blood flow resistance. Luminal internal diameter, typically ranging from 2.54 mm (0.100 in.) to 5.08 mm (0.200 in.), and relatively short length, typically 10 cm to 20 cm can have a range of lengths. A low system blood flow resistance is desirable because it allows blood flow to be maximized during a period of the procedure when the risk of embolism is greatest. As discussed in detail below, low system blood flow resistance also allows the use of variable blood flow resistance to control blood flow through the system. The dimensions of venous return sheath 910 are approximately the same as the dimensions of arterial access sheath 605 described above. No extension is required for the hemostasis valve 1010 within the venous return sheath.

Retrograde Shunt
The shunt 120 provides fluid communication between the arterial access catheter 110 and the venous return catheter 115 and may be formed from a single tube or multiple connecting tubes that provide a path for counter-flowing blood flow between them. can. As shown in FIG. 1A, the shunt 120 connects at one end to the blood flow line 615 of the arterial access device 110 (via connector 127a) and at the other end to the venous return catheter 115 (via connector 127b). blood flow line 915.

In some embodiments, shunt 120 can be formed of at least one tube that communicates with blood flow control assembly 125. Shunt 120 can be any structure that provides a fluid pathway for blood flow. Shunt 120 can have a single lumen or can have multiple lumens. Shunt 120 may be removably attached to blood flow control assembly 125, arterial access device 110, and/or venous return device 115. Prior to use, the user can select the optimal length of shunt 120 for use in the arterial access and venous return locations. In some embodiments, shunt 120 may include one or more extension tubes that can be used to change the length of shunt 120. Extension tubes can be modularly attached to shunt 120 to achieve the desired length. The modular aspect of shunt 120 allows the user to extend shunt 120 depending on the venous return site as needed. For example, in some patients, the internal jugular vein IJV is small and/or tortuous. The risk of complications at this location may be higher than elsewhere due to its proximity to other tissue structures. Additionally, neck hematomas may cause airway obstruction and/or cerebrovascular complications. Therefore, for such patients, it may be desirable to place the venous return site somewhere other than the internal jugular vein IJV, such as the femoral vein. A femoral vein return site may be achieved percutaneously with a low risk of serious complications, and also provides an alternative venous access to the central vein if an internal jugular vein IJV is not available. Additionally, the femoral venous return changes the layout of the backflow shunt so that the shunt control is placed closer to the "working area" of the intervention where the device is introduced and the contrast injection port is located. do.

In one embodiment, the shunt 120 has an inner diameter of 3/16 inch and a length of 40 to 70 cm. As mentioned above, the length of the shunt can be adjusted. In certain embodiments, the connector between the shunt and the arterial and/or venous access device is configured to minimize blood flow resistance. In some embodiments, an arterial access sheath 110, a backflow shunt 120, and a venous return sheath 115 are combined to create a low blood flow resistance arteriovenous AV shunt, as shown in FIGS. 1A-1D. As mentioned above, all these device connections and blood flow lines are optimized to minimize or reduce blood flow resistance. In certain embodiments, the AV shunt is configured to absorb blood up to 300 mL/min when there is no device within the arterial sheath 110 and the AV shunt is connected to a fluid source with a viscosity of blood and a static pressure of 60 mm Hg water pressure. Has a blood flow resistance that allows flow. The actual shunt resistance may vary depending on the presence or absence of a check valve 1115 or filter 1145 (as shown in Figure 11), or the length of the shunt, and may range from 150 to 300 mL/min. blood flow may be possible.

If there is a device such as a stent delivery catheter within the arterial sheath, there is a portion of the arterial sheath that increases blood flow resistance, which in turn increases blood flow resistance across the AV shunt. This increase in blood flow resistance has a corresponding decrease in blood flow. In some embodiments, a Y arm 620, as shown in FIG. 6A, connects the arterial sheath body 605 to a blood flow line 615 a short distance from a hemostasis valve 625 that introduces the catheter into the sheath. This distance is set by the length of proximal extension 610. The portion of the arterial sheath that is restricted by the catheter is therefore limited to the length of the sheath body 605. The actual blood flow restriction depends on the length and inner diameter of the sheath body 605 and the outer diameter of the catheter. As mentioned above, the sheath length may range from 5 to 15 cm, typically 10 to 12 cm, and the inner diameter is typically 7 Fr to 10 Fr (1 Fr = 0.33 mm), typically 8 Fr. It is. Stent delivery catheters can range from 3.7Fr to 5.0Fr or 6.0Fr, depending on the size of the stent and manufacturer. As shown in FIG. 6B, this limitation can be further reduced if the sheath body is designed to have an increased inner diameter in a portion other than within the blood vessel (stepped sheath body). Because blood flow restriction is proportional to the fourth power of the lumen distance, a small increase in lumen or annular area results in a large decrease in blood flow restriction.

The actual blood flow through the AV shunt during use is further dependent on the patient's cerebral blood pressure and blood flow resistance.

Flow Control Assembly - Reflux Regulation and Monitoring The flow control assembly 125 interacts with a reflux shunt 120 to direct the flow from the common carotid artery to a venous return site, such as the femoral vein, internal jugular vein, or external receptacle 130. Adjust and/or monitor the rate of reflux to. In this regard, the blood flow control assembly 125 allows the user to achieve a higher maximum blood flow rate than existing systems and also allows the user to selectively adjust, set, or adjust the reverse blood flow rate. . Various mechanisms can be utilized to adjust the rate of reflux, as described more fully below. As described below, blood flow control assembly 125 allows a user to configure counterflow blood flow in a manner suitable for various treatment modalities.

In general, the ability to control continuous regurgitation rate allows the physician to adjust the protocol for the individual patient and stage of surgery. Regurgitant blood flow velocity is typically controlled over a range of slow to fast speeds. The high speed is at least two times faster than the low speed, typically at least three times faster than the low speed, and often at least five times faster than the low speed. In some embodiments, the high speed is at least 3 times faster than the low speed, and in other embodiments the high speed is at least 6 times faster than the low speed. Although it is generally desirable to have a high rate of retrograde blood flow to maximize extraction of emboli from the carotid artery, patients' ability to tolerate retrograde blood flow varies. Thus, by having systems and protocols that can easily adjust the rate of reversed blood flow, the treating physician can determine when the rate of blood flow exceeds a level that is tolerated by the patient and respond accordingly. Backflow speed can be set. For patients who cannot tolerate continuous high regurgitant flow rates, physicians may choose to activate high-velocity blood flow only for short periods when the risk of embolic debris is highest and the procedure is dangerous. For short intervals, eg 15 seconds to 1 minute, patient tolerance limits are usually not a factor.

In certain embodiments, the continuous retrograde blood flow rate can be controlled with a baseline blood flow rate in the range of 10 ml/min to 200 ml/min, typically in the range of 20 ml/min to 100 ml/min. Can be controlled. These blood flow rates are tolerated by the majority of patients. During most of the procedure, the blood flow rate is maintained at the baseline blood flow rate, but when the risk of embolic release increases, the blood flow rate is shortened to increase the ability to capture such emboli. Only time can be increased beyond the baseline. Increasing retrograde blood flow velocity above baseline, for example, when a stent catheter is introduced, when a stent is deployed, before and after stent expansion, and when a common carotid artery occlusion is removed. I can do it.

The blood flow velocity control system operates between relatively low and relatively high blood flow velocities before reestablishing antegrade blood flow in order to "flush" the carotid arteries in the area of the carotid bifurcation. can be repeated. Such repetition can establish a high blood flow rate that is approximately 2-6 times faster than a low blood flow rate, typically about 3 times faster. The period of repetition can typically have a length in the range of 0.5 seconds to 10 seconds, usually 2 seconds to 5 seconds, and the total duration of the repetition is 5 seconds to 60 seconds. range, typically 10 seconds to 30 seconds.

FIG. 11 shows an embodiment of a system 100 that includes a layout of a blood flow control assembly 125, where the counterflowing blood flow passes through at least a portion of the blood flow control assembly 125. or is placed along the shunt 120 in communication with the shunt 120. Blood flow control assembly 125 can include various controllable mechanisms for regulating and/or monitoring reflux. The mechanism can include various means for backflow control, including one or more pumps 1110, valves 1115, syringes 1120, and/or variable resistance components 1125. Blood flow control assembly 125 can be controlled manually by a user and/or automatically via controller 1130 to alter blood flow through shunt 120. For example, by changing the blood flow resistance, the rate of blood flow back through the shunt 120 can be controlled. Controller 1130 (described in more detail below) can be integrated into blood flow control assembly 125 or can be a separate component in communication with components of blood flow control assembly 125.

Additionally, the blood flow control assembly 125 includes one or more flow sensors 1135 and/or anatomical data sensors 1140 (detailed below) to detect one or more conditions of regurgitation. ) may be included. A filter 1145 can be placed along the shunt 120 to remove emboli before blood returns to the venous return site. When the filter 1145 is placed upstream of the controller 1130, the filter 1145 can prevent emboli from entering the controller 1145 and packing the variable flow resistance component 1125. Various components of blood flow control assembly 125 (including pump 1110, valve 1115, syringe 1120, variable resistance component 1125, sensor 1135/1140 and filter 1145) can be positioned at various locations along shunt 120, and It should be appreciated that they can be located in various positions upstream or downstream with respect to each other. The components of blood flow control assembly 125 are not limited to the locations shown in FIG. 11. Furthermore, blood flow control assembly 125 does not necessarily include all components, but rather may include various sub-combinations of components. For example, a syringe can optionally be used within the blood flow control assembly 125 for the purpose of regulating blood flow or delivering a fluid, such as a radiocontrast agent, into an artery in an antegrade direction through the shunt 120. As introduced, it can also be used external to the assembly for purposes other than blood flow regulation.

Both variable resistance component 1125 and pump 1110 can be coupled to shunt 120 to control the rate of retrograde blood flow. Variable resistance component 1125 controls blood flow resistance while pump 1110 provides positive displacement through shunt 120. Thus, rather than relying on ECA and ICA perfusion stump pressures and venous back pressure to drive backflow, the pump can be activated to drive backflow. Pump 1110 can be any type of pump including a peristaltic tube pump or a positive displacement pump. Pump 1110 can be activated or deactivated (manually or automatically via controller 1130) to selectively effect blood movement through shunt 120 and to control the rate of blood flow through shunt 120. Blood movement through the shunt 120 can also be accomplished by other methods, including using a suction syringe 1120, or a suction source such as a vacutainer, vaculock syringe, or wall suction. Pump 1110 can communicate with controller 1130.

One or more blood flow control valves 1115 can be placed along the path of the shunt. The valve can be moved manually or automatically (via controller 1130). Flow control valve 1115 may be, for example, a one-way valve to prevent blood flow in the antegrade direction within shunt 120, a check valve, or, for example, contrast agent injection at high pressure (they may be in the antegrade direction). The shunt 120 can be a high pressure valve that closes the shunt 120 (intended to enter the arterial blood vessel). In certain embodiments, the one-way valve is a low flow resistance valve, such as those described in US Pat. No. 5,727,594 or other low flow resistance valves.

In some embodiments of the shunt that include both a filter 1145 and a one-way check valve 1115, the check valve is located downstream of the filter. In this manner, as debris advances into the shunt, it is trapped in the filter before reaching the check valve. Many check valve configurations include a sealing member that seals the housing containing the blood flow lumen. Debris can become trapped between the seal and the housing, thus compromising the valve's ability to seal against back pressure.

Controller 1130 is in communication with components of system 100 including blood flow control assembly 125, including, for example, shunt 120, arterial access device 110, venous return device 115, and flow control assembly 125. through which manual and/or automatic adjustment and/or monitoring of reflux is possible. For example, a user may move one or more actuators on controller 1130 to manually control components of blood flow control assembly 125. Manual controls may include switches, dials, or similar components located directly on controller 1130, or components located remotely from controller 1130, such as, for example, a foot pedal or similar device. Controller 1130 can also automatically control components of system 100 without requiring input from a user. In some embodiments, a user can program software into controller 1130 to enable such automatic control. Controller 1130 can control the operation of mechanical portions of blood flow control assembly 125. The controller 1130 includes electrical circuitry or programming that interprets the signals generated by the sensors 1135/1140 so that the controller 1130 can control the operation of the blood flow control assembly 125 in response to the signals generated by the sensors. be able to.

The depiction of controller 1130 in FIG. 11 is merely exemplary. It should be appreciated that controller 1130 can vary in appearance and structure. In FIG. 11, controller 1130 is shown as being integrated into a single housing. This allows a user to control blood flow control assembly 125 from one location. It should be appreciated that any components of controller 1130 can be distributed in separate housings. Additionally, FIG. 11 illustrates controller 1130 and blood flow control assembly 125 as separate housings. It should be appreciated that the controller 1130 and blood flow control regulator 125 can be integrated into a single housing or can be split into multiple housings or multiple components.

Flow State Indicator(s)
Controller 1130 can include one or more indicators that provide visual and/or audio signals to the user regarding the condition of the reflux. The audio display is advantageous in making the user aware of blood flow conditions without requiring the user to visually check the blood flow controller 1130. The indicator may include a speaker 1150 and/or a light 1155, or any other means for communicating the backflow condition to the user. Controller 1130 can control operation of the indicator in communication with one or more sensors of the system. Alternatively, actuation of the indicator may be directly coupled to a user moving one of the blood flow control actuators 1165. The indicator need not be a speaker or a light. The indicator can be simply a button or switch that visually indicates the condition of reflux. For example, a button in a certain state (eg, pressed or down) may provide a visual indication of a fast regurgitation state. Alternatively, a switch or dial pointing to a particular labeled blood flow condition may provide a visual indication that reflux is in the labeled condition.

The indicator can provide a signal indicating one or more conditions of reflux. In some embodiments, the indicator identifies only two distinct conditions: a “high” blood flow rate condition and a “low” blood flow rate condition. In another embodiment, the indicator identifies more than one blood flow rate and includes a "high" blood flow rate, a "medium" blood flow rate, and a "low" blood flow rate. The indicator can be configured to identify any quantity of a discrete condition of reflux, or can identify a graduated signal corresponding to a condition of reflux. In that case, the indicator can be a digital or analog meter 1160 that indicates a value of reflux rate, such as ml/min or other units.

In some embodiments, the indicator is configured to indicate to the user whether the reflux rate is a "high" blood flow rate condition or a "low" blood flow rate condition. For example, the indicator may brighten in a first manner (e.g., level of brightness) and/or emit a first audio signal when the blood flow rate is high; When low, it changes to a second modality of brightness and/or emits a second audio signal. Alternatively, the indicator may become brighter and/or emit an audio signal only when the blood flow rate is high or only when the blood flow rate is low. Considering that some patients cannot tolerate high blood flow rates or cannot tolerate high blood flow rates for more than an extended period of time, the indicator provides a warning to the user when the blood flow rate is high. It would be advisable to provide notice. This serves as a fail-safe feature.

In another embodiment, the indicator provides a signal (audible and/or visual target). In another embodiment, the indicator provides a signal when no backflow is present, such as when the shunt 120 is blocked or when one of the plugs of the shunt 120 is closed.

Flow Rate Actuators
Controller 1130 includes one or more actuators that a user can press, switch, manipulate, or actuate to adjust the rate of retrograde blood flow and/or Blood flow velocity can be monitored. For example, the controller 1130 can include a blood flow control actuator 1165 (e.g., one or more buttons, knobs, dials, switches, etc.) that can be moved by the user so that the controller selectively changes the manner of regurgitation. . For example, in the illustrated embodiment, blood flow control actuator 1165 is a knob that can be rotated to various discrete positions, each corresponding to controller 1130 that causes system 100 to achieve a particular reflux condition. These states include, for example, (a) OFF state, (b) LO-FLOW state, (c) HI-FLOW state, and (d) ASPIRATE state. Contains. It should be appreciated that the conditions described above are merely exemplary and that different conditions or combinations of conditions may also be utilized. Controller 1130 achieves various reflux conditions by interacting with one or more components of the system, including sensors, valves, variable resistance components, and/or pumps. It should be appreciated that the controller 1130 can also include electrical circuitry and software to adjust the regurgitation rate and/or monitor the blood flow rate without the user having to actively move the controller 1130. .

The off state corresponds to the absence of retrograde blood flow through the shunt 120. When the user sets the flow control actuator 1165 off, the controller 1130 stops backflow, such as by tightening the valve or closing the stopper of the shunt 120. Low and high flow conditions correspond to low and high reflux rates, respectively. When a user sets blood flow control actuator 1165 to low or high flow, controller 1130 interacts with the components of blood flow control 125, including pump 1110, valve 1115, and/or variable resistance component 1125, to Increase or decrease blood flow velocity accordingly. Finally, if active backflow is desired, the suction state corresponds to opening the circuit to a suction source (eg, a vacutina or suction device).

The system can be utilized to alter blood flow between various states, including active, passive, suction, and off states. The active state corresponds to a system that uses means to actively drive blood flow back. Such active means can include, for example, a pump, a syringe, a vacuum source, and the like. The passive state corresponds to when retrograde blood flow is driven by the perfusion stem pressure of the ECA and ICA and possibly by the venous pressure. The suction state corresponds to a system that uses a suction source (eg, a vacutina or suction device) to drive blood flow backwards. The off state corresponds to a system in which there is no backflow of blood, such as the result of closing a spigot or valve. Low blood flow velocity and high blood flow velocity can be either passive or active blood flow conditions. In some embodiments, specific values for either low blood flow rate and/or high blood flow rate (e.g., in ml/min) are configured within the controller so that the user does not actually set or enter the values. Can be predetermined and/or preprogrammed. More precisely, the user simply selects "high blood flow" and/or "low blood flow" (e.g., by pressing an actuator, such as a button on controller 1130), and controller 1130 controls blood flow control assembly 125. the blood flow velocity to a predetermined high blood flow velocity value or low blood flow velocity value. In another embodiment, the user sets or inputs low blood flow rate and/or high blood flow rate values, eg, into the controller. In another embodiment, low blood flow rates and/or high blood flow rates are not actually set. More precisely, external data (eg, data from anatomical data sensor 1140, etc.) is used as a basis for influencing blood flow velocity.

The blood flow control actuator 1165 may be a plurality of actuators, such as one actuator (e.g., a button or switch) for switching the state from a low-flow state to a high-flow state; Another actuator is to close the blood flow loop and turn it off during injection of contrast agent when directed to the carotid artery. In some embodiments, blood flow control actuator 1165 can include multiple actuators. For example, one actuator can be operated to switch the blood flow rate from low to high speed, another actuator can be operated to temporarily stop the blood flow, and a third actuator (e.g. a plug) can be operated to temporarily stop blood flow. can be operated and aspirated using a syringe. In another example, one actuator is operated to switch to a low flow state and another actuator is operated to switch to a high flow state. Alternatively, the blood flow control actuator 1165 may include multiple actuators for switching from a low flow state to a high flow state, and additional actuators for finely adjusting the blood flow rate between high and low blood flow rates. and may include. When switching between low and high flow states, these additional actuators can be used to fine-tune the blood flow rate between those states. Thus, it should be understood that the various blood flow rates can be dialed in and fine-tuned for each condition (ie, high and low blood flow conditions). Control over blood flow conditions can be achieved using a wide variety of actuators.

Controller 1130, or individual components of controller 1130, can be placed in various positions relative to the patient and/or relative to other components of system 100. For example, when introducing an interventional tool into a patient, the blood flow control actuator 1165 can be placed near the hemostasis valve to facilitate access to the blood flow control actuator 1165 during tool introduction. As shown in FIGS. 1A-C, the placement location may vary based on, for example, whether a transfemoral or transcervical approach is used. Controller 1130 may have wireless and/or adjustable length wired connections to the rest of system 100 to allow remote control of system 100. Controller 1130 can have a wireless connection and/or an adjustable length wired connection with blood flow control regulator 125 to allow remote control of blood flow control regulator 125. Controller 1130 can also be integrated into blood flow control regulator 125. When controller 1130 is mechanically connected to a component of blood flow control assembly 125, controller 1130 can be connected to one or more components with a tether of mechanical operating capabilities. In some embodiments, the controller 1130 can be located at a sufficient distance from the system 100 so that the controller 1130 is outside the radiation field when fluoroscopy is being used.

Controller 1130 and its components can interact with other components of the system (eg, pumps, sensors, shunts, etc.) in a variety of ways. For example, various mechanical connections may be used to enable communication between controller 1130 and components of the system. Alternatively, controller 1130 can communicate electronically or magnetically with the components of the system. Electromechanical connections can also be used. Controller 1130 may be equipped with control software that allows the controller to implement functionality to control components of the system. The controller itself can be a mechanical, electrical, or electromechanical device. The controller can be moved mechanically, pneumatically, or hydraulically, or electromechanically (eg, as in the case of solenoid operation in blood flow control conditions). Controller 1130 can include a computer, computer processor, and memory, as well as data storage capabilities.

FIG. 12 shows an exemplary embodiment of a variable blood flow control element 1125. In this embodiment, the resistance to blood flow through the shunt 120 may be altered by providing two or more alternative blood flow paths creating low and high resistance blood flow paths. As shown in FIG. 12A, blood flow through shunt 120 passes through primary lumen 1700 and secondary lumen 1705. Secondary lumen 1705 is longer and/or has a smaller radius than primary lumen 1700. Therefore, second lumen 1705 has a higher blood flow resistance than primary lumen 1700. Blood flow through both of these lumens provides a minimum resistance to blood flow. Blood can flow through both lumens 1700 and 1705 due to the drop in blood pressure created in the main lumen 1700 across the inlet and outlet of the second lumen 1705. This has the advantage of preventing blood stagnation. As shown in FIG. 12B, by blocking blood flow through the main lumen 1700 of the shunt 120, all blood flow is diverted to the second lumen 1705, thus increasing blood flow resistance and increasing blood flow velocity. decreases. It should be appreciated that additional blood flow lumens may be provided, allowing three, four or more separate parallel blood flow resistances. Shunt 120 may include a valve 1710 that controls blood flow to primary lumen 1700 and secondary lumen 1705. The position of the valve may be controlled by an actuator, such as a button or switch on the housing of the blood flow controller 125. The embodiment of FIGS. 12A and 12B is advantageous in that even in the slowest blood flow settings, this embodiment maintains accurate blood flow lumen size. The size of the second blood flow lumen can be configured to prevent thrombus formation even under conditions of slowest or sustained blood flow. In some embodiments, the inner lumen diameter of second lumen 1705 is 0.063 inches or greater.

13A-C illustrate an embodiment of a blood flow controller 125 that includes many blood flow shunt components and features contained or encapsulated in a single housing 1300. This configuration simplifies and reduces the space required for blood flow controller 125 and blood flow shunt 120. As shown in FIG. 13A, housing 1300 includes a variable blood flow element 1125 of the type illustrated in FIG. Actuator 1330 moves valve 1710 back and forth, transitioning the blood flow resistance within the shunt between a low resistance state and a high resistance state. In FIG. 13A, the valve is in the open position with the shunt in a low resistance (high flow) state. In Figure 13B, the valve is in the closed position and the shunt is in a high resistance (low flow) state. The second actuator 1340 moves the second valve 1720 back and forth to open and close the shunt line 120. In FIGS. 13A and 13B, valve 1720 is in an open position, allowing blood flow through shunt 120. In FIG. 13C, valve 1720 is in the closed position, completely stopping blood flow within shunt 120. Housing 1300 also includes a filter 1145 and one-way check valve 1115. In some embodiments, the housing may be opened and filter 1145 removed after the procedure. This embodiment has the advantage that the filter may be rinsed and inspected after the procedure so that the physician can have direct visual evidence of the embolic debris captured by the system during the procedure. .

In a preferred embodiment, the connectors connecting the elements of the reflux system are large diameter, quick-connect type connectors. For example, the male large bore hub 680 on the Y adapter 660 of the arterial sheath 110 as shown in FIG. Connect with. Similarly, a male large bore connector 1310 on the venous side of the blood flow shunt 120 connects with a female counterpart connector 1310 on the blood flow line of the venous sheath 115 as shown in FIG. 10C. A connected backflow system 100 is shown in FIG. 1E. This preferred embodiment reduces blood flow resistance through the blood flow shunt, thus allowing faster blood flow rates, and also allows for faster blood flow rates (with a misplaced check valve) if the blood flow shunt is inadvertently connected in reverse. prevent In alternative embodiments, the connections are standard female and male Luer connectors or other types of tubing connectors.

<Sensor>
As mentioned above, blood flow control assembly 125 can include or interact with one or more sensors, which is in communication with system 100 and/or which is in communication with the patient's tissue. I'm in touch. Each of the sensors may be suitable for responding to a physical stimulus (including, for example, heat, light, sound, pressure, magnetism, motion, etc.) and for measurement or display or operation of controller 1130. It may be suitable for transmitting signals obtained for use. In some embodiments, blood flow sensor 1135 interacts with shunt 120 to sense conditions of blood flow through shunt 120 (eg, blood flow rate or volumetric flow rate, etc.). Blood flow sensor 1135 can be directly coupled to a display that directly displays blood flow volume flow or flow rate values. Alternatively, blood flow sensor 1135 can input volume flow or flow rate data to controller 1130 for display.

The type of blood flow sensor 1135 can be changed. Blood flow sensor 1135 can be a mechanical device such as, for example, a paddle wheel, a flapper valve, a rolling ball, or a mechanical component responsive to blood flow through shunt 120. It's okay. Movement of the mechanical device in response to blood flow through the shunt 120 can serve as a visual indication of flow rate and can also be calibrated to a scale as a visual indication of fluid flow rate. Mechanical devices can be coupled to electrical components. For example, a paddle wheel can be positioned within the shunt 120 such that the flow rate causes the paddle wheel to rotate; the greater the velocity of the flow rate, the greater the rotation rate of the paddle wheel. The paddle wheel can be magnetically coupled to a Hall effect sensor to detect rotational speed, which is indicative of the flow rate through the shunt 120.

In some embodiments, blood flow sensor 1135 is an ultrasonic or electromagnetic or electro-optic flow meter that allows blood flow measurements through the wall of shunt 120 without contacting blood. The ultrasonic or electromagnetic flow meter can be configured so that it does not need to be in contact with the lumen of the shunt 120. In embodiments, blood flow sensor 1135 includes at least in part a Doppler flow meter (eg, a transonic flow meter) that measures flow through shunt 120. In another embodiment, the blood flow sensor 1135 measures the pressure difference along the blood flow line to determine the flow rate. It should be appreciated that a wide variety of sensor types can be used, including ultrasonic flow meters and transducers. Additionally, the system can include multiple sensors.

System 100 is not limited to using a blood flow sensor 1135 located within shunt 120 or interacting with venous return device 115 or arterial access device 110. For example, anatomical data sensor 1140 can communicate with or interact with patient tissue (eg, patient neurological tissue, etc.). In this manner, the anatomical data sensor 1140 can sense measurable tissue conditions that are directly or indirectly related to the rate of regurgitation from the carotid artery. For example, the anatomical data sensor 1140 can measure blood flow conditions within the brain (e.g., middle cerebral artery blood flow velocity) and display and/or display on the controller 1130 to adjust the regurgitant flow velocity based on predetermined criteria. , can convey such conditions. In some embodiments, anatomical data sensor 1140 includes transcranial Doppler sonography (TCD), which is an ultrasound test that uses reflected sound waves to assess blood flowing through the brain. Use of the TCD results in a TCD signal that can be communicated to the controller 1130 to control the reverse flow rate to achieve or maintain the desired TCD profile. Anatomical data sensor 1140 can be based on physiological measurements, including reflux velocity, blood flow through the middle cerebral artery, TCD signals of embolic particles, or other neuromonitoring signals.

In some embodiments, system 100 includes a closed loop control system. In a closed loop control system, one or more sensors (such as blood flow sensor 1135 or anatomical data sensor 1140) sense a predetermined condition of system 100 or tissue (such as regurgitation rate and/or neurological monitoring signals). or monitor. The sensors input relevant data to a controller 1130 that continuously adjusts system conditions as necessary to maintain the desired reverse flow rate. The sensor determines how the system 100 operates the controller 1130 so that the controller 1130 can translate that data and move components of the blood flow control regulator 125 to dynamically compensate for perturbations to the flow rate. Give feedback on how you are doing. For example, controller 1130 may include software that causes controller 1130 to send signals to components of blood flow control assembly 125 to maintain a constant blood flow rate despite varying blood pressures from the patient. Adjust the blood flow rate so that In this embodiment, the system 100 does not need to rely on the user to determine when, for how long, and/or at what value to set the reflux rate to a high or low state. . Rather, software within controller 1130 may govern such factors. In a closed loop system, the controller 1130 controls the components of the blood flow control assembly 125 to determine the level or condition of regurgitation (eg, analog level or high, low, baseline, Any of the discrete states (such as intermediate) can be established.

In embodiments, anatomical data sensor 1140 (which measures physiological measurements of the patient) communicates a signal to controller 1130, which adjusts blood flow rate based on the signal. For example, physiological measurements may be based on flow rate through the MCA, TCD signals, or other cerebrovascular signals. In the case of TCD signals, TCD may be used to monitor cerebral blood flow changes and detect microemboli. Controller 1130 may adjust the blood flow rate to maintain the TCD signal within a desired profile. For example, the TCD signal may indicate the presence of a microembolus ("TCD hits") and the controller 1130 may adjust the regurgitant blood flow rate to maintain the TCD hits below the TCD hits threshold. I can do it. (Ribo et al., "Transcranial Doppler Monitoring of Transcervical Carotid Stenting with Flow Reversal Protection: A Novel Carotid Revascularization Technique" )" Stoke 2006, 37, 2846-2849, Shekel et al., "Experience of 500 Cases of Neurophysiological Monitoring in Carotid Endarterectomy", Acta Neurochir, 2007 , 149:681-689, incorporated herein by reference in their entirety).

For MCA blood flow, the controller 1130 can set the reverse flow rate to the "maximum" blood flow rate that the patient can tolerate, as assessed by perfusion to the brain. The controller 1130 can control the regurgitation rate to optimize the level of patient protection without relying on user intervention. In another embodiment, the feedback is based on the status of devices in system 100 or intervention tools used. For example, the sensor may notify controller 1130 when system 100 is in a high-risk state (eg, when an interventional catheter is located within sheath 605). Controller 1130 then adjusts the blood flow rate to compensate for such conditions.

Controller 1130 can be used to selectively increase reflux in various ways. For example, it has been observed that greater regurgitation velocity results in a greater drop in blood flow towards the brain, where the most important is the ipsilateral MCA, which is associated with collateral blood flow from the circle of Willis. may not be adequately compensated. Thus, high reflux rates over a long period of time can cause a situation in which the patient's brain does not receive sufficient blood flow, which the patient cannot tolerate and may manifest as neurological symptoms. Studies indicate that MCA blood flow velocity of less than 10 cm/sec is the threshold below which patients are at risk of neurological blood deficiency. There are other markers (such as EEG signals) to monitor adequate perfusion to the brain. However, even high blood flow rates that lead to complete cessation of blood flow to the MCA may be tolerated for short periods of time, within approximately 15 seconds to 1 minute.

In this way, the controller 1130 can optimize embolic debris capture by automatically increasing backflow for limited periods of time that correspond to periods of high risk of embolization during surgery. The period of high risk includes the period in which the interventional device (dilatation balloon or stent delivery device before and after stent expansion) crosses the plaque P. Another period is during interventional operations, such as inflation or deflation of a balloon before or after deployment or expansion of a stent. The third period is during contrast agent injection for angiographic imaging of the treatment area. During periods of low risk, the controller can return the regurgitation rate to a lower baseline level. This lower level may correspond to a low retrograde flow rate within the ICA, or may correspond to a slight antegrade blood flow within the patient with a high perfusion pressure ratio of the ECA to the ICA.

In a blood flow control system where the user manually sets the blood flow state, there is a risk that the user may not pay attention to the backflow state (high or low) and inadvertently hold the circuit at high blood flow. This will later cause adverse patient reactions. In some embodiments, the initial value of blood flow velocity is a low blood flow velocity as a safety mechanism. This serves as a fail-safe measure for patients who cannot tolerate high blood flow rates. In this regard, the controller 1130 can be biased toward an initial value of velocity such that after a predetermined period of time at the high blood flow rate, the system is returned to the lower blood flow rate by the controller. Biasing toward lower blood flow rates can be accomplished by electronics or software, or can be accomplished using mechanical components or a combination thereof. In some embodiments, the blood flow control actuator 1165 and/or the valve 1115 of the controller 1130 and/or the pump 1110 of the blood flow control regulator 125 are spring loaded toward a state that achieves a low blood flow rate. Controller 1130 is configured to allow a user to override controller 1130 so that the system can be manually returned to a lower blood flow rate state if desired.

In another safety mechanism, controller 1130 includes a timer 1170 (FIG. 11) that keeps track of how long the high blood flow rate is present. The controller 1130 can be programmed to automatically return the system 100 to the lower blood flow rate after a predetermined period of time (eg, 15, 30, 60 seconds or more) at the higher blood flow rate. After the controller returns to the lower blood flow rate, the user can initiate another predetermined period of higher blood flow rate, if desired. Additionally, a user can override controller 1130 to move system 100 to a desired lower blood flow rate (or higher blood flow rate).

An exemplary procedure involves initially setting a slow regurgitation level and then switching to a high speed for discrete periods during the critical phase of the procedure to reduce embolic debris flow without creating patient tolerance problems. Optimize capture. Instead, the blood flow rate is initially set to a high rate and the patient's tolerance to that level is confirmed before continuing with the rest of the procedure. Reduce the reflux rate if the patient shows signs of intolerance. Patient tolerance may be determined automatically by the controller based on feedback from anatomical data sensor 1140, or by a user based on observations of the patient. Adjustment of the backflow rate can be done automatically by the controller or manually by the user. Alternatively, the user may monitor the flow rate through the middle cerebral artery (MCA) using, for example, a TCD and set the maximum level of regurgitant flow that maintains the MCA flow rate above a threshold level. In this situation, the entire procedure may be performed without modifying the blood flow status. If the flow rate of the MCA changes during the course of the procedure, or if the patient exhibits neurological symptoms, necessary adjustments will be made.

Exemplary Kit Composition and Package Design In an exemplary embodiment of the reflux system 100, all components of the reflux system include an arterial sheath, an arterial sheath dilator, a venous sheath, a venous sheath dilator, a blood flow shunt/ The blood flow controller and one or more sheath guidewires are packaged together in a single, sterile package. In one configuration, the components are mounted on a flat card, such as a cardboard or polymer card, that has one or more openings or cutouts sized and shaped to receive and close the components. In another configuration, the card is configured to open and close like a book or in any clamshell fashion to reduce the package profile. In this embodiment, the card may have a cutout such that at least a portion of the product is visible when in the closed configuration. FIG. 15A shows the kit riding on a book card 1510 in an open configuration. FIG. 15B shows a kit with book cards in a closed configuration. Cutout 1520 allows visualization of at least one portion of the packaged device, such as blood flow controller housing 1300, even when the card is in a closed configuration. FIG. 15C shows the kit and book card inserted into additional packaging components, including a sterile bag 1530 and a shelf carton 1540. In this embodiment, the shelf carton 1540 is also aligned with the cutout 1520 in the book card, as shown in FIG. 15D, allowing visualization of at least a portion of the product from outside the closed shelf carton. Includes 1550 clips. Nylon or other transparent film material may be applied to the window of the shelf carton to protect the sterile bag from dirt or damage.

In some embodiments, a packaging card, either flat or book type, is printed with component names, connection instructions, and/or adjustment instructions to assist in adjusting and using the device. It's okay.

In an alternative embodiment, the arterial access device, venous return device, and blood flow shunt with blood flow controller are packaged in three separate sterile packages. For example, an arterial access device, including an arterial access sheath, a sheath dilator, and a sheath guidewire, is placed in a first sterile package, and a venous return device, including a venous return sheath, a venous sheath dilator, and a sheath guidewire, is placed in a second sterile package. and place the blood flow shunt with blood flow controller into a third sterile package.

Illustrative Methods of Use Referring to FIGS. 14A-14E, blood flow through the carotid bifurcation at different stages of the method disclosed herein is illustrated. Initially, the distal sheath 605 of the arterial access device 110 is introduced into the common carotid artery CCA, as shown in FIG. 14A. As mentioned above, entry into the common carotid artery CCA may be made via a transcervical or transfemoral approach, either through direct surgical incision or percutaneous access. After the sheath 605 of the arterial access device 110 is introduced into the common carotid artery CCA, blood flow continues in the antegrade direction AG, as shown in FIG. 14A, from the common carotid artery to the internal carotid artery ICA and the external carotid artery Both will be in the ECA.

The venous return device 115 is then inserted into a venous return site, such as the internal jugular vein IJV (not shown in FIGS. 14A-14E) or the femoral vein. Shunt 120 is used to connect blood flow lines 615 and 915 of arterial access device 110 and venous return device 115, respectively (as shown in FIG. 1A). In this manner, shunt 120 provides a path for backflow from arterial access device 110 to venous return device 115. In another embodiment, as shown in FIG. 1C, shunt 120 connects to external receptacle 130 rather than venous return device 115.

Once all components of the system are in place and connected, blood flow through the common carotid artery CCA is stopped, typically by occluding the common carotid artery CCA using a tourniquet 2105 or other external vaso-occlusion device. In an alternative embodiment, occlusion element 129 is located at the distal end of arterial access device 110. Alternatively, as shown in FIG. 2B, occlusion element 129 is introduced with second occlusion device 112 separate from distal sheath 605 of arterial access device 110. The ECA may be occluded with separate occlusion elements on the same device 110 or on separate occlusion devices.

At that point, retrograde flow RG from the external carotid artery ECA and internal carotid artery ICA will begin and flow through sheath 605, blood flow line 615, shunt 120, and via blood flow line 915 to venous return device 115. Blood flow control assembly l25 regulates backflow as described above. FIG. 14B shows the occurrence of backflow RG. While reflux is maintained, a stent delivery catheter 2110 is introduced into the sheath 605, as shown in FIG. 14C. Stent delivery catheter 2110 is introduced into sheath 605 through hemostatic valve 615 and proximal extension 610 of arterial access device 110 (not shown in FIGS. 14A-14E). As shown in FIG. 14D, stent delivery catheter 2110 is advanced into the internal carotid artery ICA and stent 2115 is deployed at bifurcation B.

For example, the reflux rate can be increased during periods of high risk of embolization, such as while the stent delivery catheter 2110 is being introduced and, optionally, the stent 2115 is being deployed. Backflow rates can also be increased during deployment and inflation of the dilatation balloon before and after stent deployment. Prior to stenting, atherectomy can also be performed under reflux conditions.

Optionally, after expansion of stent 2115, bifurcation B can be flushed out by cycling back and forth between lower and higher blood flow velocities. The area of the carotid artery where a stent was deployed or other procedure was performed may be flushed with blood before normal blood flow is reestablished. In particular, while the common carotid artery remains occluded, a balloon catheter or other occlusion element may be advanced and deployed into the internal carotid artery to completely occlude that artery. The same operation may also be used to perform a post-deployment stent dilation, which is currently typically performed in self-expanding stent procedures. Thereafter, the occluding means present in the artery may be temporarily opened to reestablish blood flow from the common carotid artery to the external carotid artery. The resulting blood flow (slow blood flow, turbulent blood flow, or stagnant blood flow during carotid artery occlusion in the external carotid artery) could flush out the common carotid artery. Additionally, forward flow may be established by placing the same balloon distal to the stent during backflow and temporarily removing and flushing the common carotid artery occlusion. In this way, a flushing action occurs in the stented area to help remove loose or loosely attached embolic debris in that area.

Optionally, while blood flow from the common carotid artery continues and the internal carotid artery remains occluded, measures can be taken to remove additional free emboli from the treated area. For example, mechanical elements may be used to clean or remove free or loosely attached plaque or other potential embolic debris within the stent, catheters that deliver thrombolytic agents or other fluids, etc. may be used to clean the area or other procedures may be performed. For example, treatment of in-stent restenosis using balloons, atherectomy, or additional stents can be performed under counterflow. In another example, the occlusion balloon catheter may include a blood flow or aspiration lumen or channel opening proximal to the balloon. Saline, thrombolytic agents, or other fluids may be injected and/or blood and debris may be aspirated from or into the treatment area without the need for additional devices. Although emboli thus released may flow into the external carotid artery, the external carotid artery is generally less sensitive to embolus release than the internal carotid artery. Prophylactic removal of remaining potential emboli further reduces the risk of emboli being released when blood flow to the internal carotid artery is reestablished. The emboli may also be released under reverse flow, resulting in the emboli flowing through the shunt 120 into the venous system, the filter within the shunt 120, or the receptacle 130.

After the embolus is removed from the bifurcation, the occlusion element 129 or alternative tourniquet 2105 can be removed to reestablish antegrade blood flow, as shown in FIG. 14E. Thereafter, sheath 605 can be removed.

At the end of the procedure and before withdrawing the sheath 605, a self-closing element may be deployed around the penetration in the wall of the common carotid artery. Typically, the self-closing element is deployed at or near the beginning of the procedure, but optionally the self-closing element is deployed when the sheath is withdrawn, often with the distal end of the sheath attached to the wall of the common carotid artery. It can also be expanded when released from above. The use of a self-closing element is advantageous because it substantially effects rapid closure of the common carotid artery penetration when the sheath is withdrawn. Such rapid closure can reduce or eliminate unintended blood loss, either at the end of the procedure or during inadvertent removal of the sheath. Furthermore, such a self-closing element would reduce the risk of dissection of the arterial wall during access. Additionally, the self-closing element may be configured to exert a frictional or other retention force on the sheath during the procedure. Such retention is advantageous and can reduce the possibility of inadvertent removal of the sheath during a procedure. The self-closing element eliminates the need for surgical closure of the artery with sutures after removing the sheath, reduces the need for a large surgical field, and significantly reduces the surgical skill required for the procedure.

A wide variety of self-closing elements may be used in the disclosed systems and methods, typically mechanical elements that include an anchor portion and a self-closing portion. The anchor portion may include a hook, pin, staple, clip, tine, suture, etc. that engages around the penetration on the external surface of the common carotid artery to ensure that the penetration is fully open. to secure the self-closing element when The self-closing element may include a spring-like or other self-closing portion that will close the anchor portion upon removal of the sheath to provide closure and draw tissue within the artery wall. Normally, the closure will be sufficient and no further steps will need to be taken to close or seal the penetration. However, optionally it may be desirable to provide an auxiliary sealing of the self-closing element after the sheath is withdrawn. For example, the self-closing element and/or tissue tract within the element may be treated with a hemostatic material such as a bioabsorbable polymer, collagen plug, adhesive, sealant, coagulation factor or other procoagulant. can do. Alternatively, the tissue or self-closing element may be sealed using other sealing protocols such as electrocautery, suturing, clipping, stapling, etc. Alternatively, the self-closing element would be a self-sealing membrane or gasket material attached to the outer wall of the blood vessel by clips, adhesives, bands or other means. A self-sealing membrane may have internal openings, such as slits or crosscuts, which would normally close against blood pressure. These self-closing elements can be designed to be placed in an open surgical procedure or to be deployed percutaneously.

In another embodiment, carotid artery stenting may be performed after placing a sheath within the external carotid artery and deploying the occlusion balloon catheter. A stent with a side hole or other element intended not to obstruct the external carotid ostium is delivered through a sheath with a guide wire or the shaft of an external carotid artery occlusion balloon received through the side hole. Ru. Thus, when a stent is typically advanced by a catheter introduced over a guide wire that extends into the internal carotid artery, the presence of the catheter shaft within the side hole may prevent the stent from being advanced when the stent is advanced. This will ensure that the lateral hole is aligned with the external carotid ostium. The side holes prevent trapping of the stent-equipped external carotid artery occlusion balloon shaft, a drawback of other blood flow reversal systems, when the occlusion balloon is deployed in the external carotid artery. This approach also avoids "jailing" the external carotid artery and obstructing blood flow to the external carotid artery when the stent is covered with graft material.

In another embodiment, a stent is installed that has a shape that substantially conforms to a pre-existing angle between the common carotid artery and the internal carotid artery. Due to significant antological variation between patients, the bifurcation between the internal and external carotid arteries may have a wide variety of angles and shapes. By providing a stent family with different geometries, or by providing individual stents that the physician can shape prior to deployment, the physician can create a stent that matches the patient's specific tissue prior to deployment. You can choose. The patient's tissues will be determined using angiography or other conventional means. As a further alternative, the stent may have portions of articulation. These stents may be first placed and then articulated in situ to match the bifurcation angle between the common and internal carotid arteries. A stent may be placed in a carotid artery, where the stent has a sidewall with zones of different density.

In another embodiment, the stent will be installed when one or both ends of the stent are at least partially covered by the graft material. Generally, the stent will be free of graft material and there will also be no intermediate portion of the stent deployed adjacent the external carotid ostium to allow blood flow from the common carotid artery to the external carotid artery.

In another embodiment, the stent delivery system can be optimized for transcervical access by being shorter and/or stiffer than systems designed for transfemoral access. These changes will enhance the ability to accurately torque and accurately position the stent during deployment. Additionally, stent delivery systems can be designed such that the stent is aligned with the external carotid ostium by using either an external carotid artery occlusion balloon or a separate guide wire within the external carotid artery, which It is particularly useful for stents with curved, bent, or angled sections in orientation-critical sections.

In some embodiments, the shunt may be fixedly connected to the arterial access sheath and the venous return sheath such that the entire replaceable blood flow assembly and sheath assembly is disposable and replaceable as a unit. In other examples, the blood flow control assembly may be removably attached to one or both sheaths.

In some embodiments, the user first determines whether there is a period of high risk for embolization during the procedure. As mentioned above, typical periods of high risk include (1) during the period in which the device traverses the plaque P; (2) such as during delivery of a stent or during inflation or deflation of a balloon catheter or guidewire. (3) during the interventional procedure, and (3) during the injection of the contrast agent. The foregoing are merely illustrative of periods of high risk. During such periods, the user sets fast reflux for individual periods. When the high-risk period is over, or if the patient exhibits intolerance to high blood flow rates, the user returns the blood flow state to baseline blood flow. If the system has a timer, the blood flow status will automatically return to baseline blood flow after a set period of time. In this case, if the procedure is still in a period of high embolic risk, the user may reset the blood flow state to a high blood flow rate.

In another embodiment, if the patient exhibits an intolerance to the presence of reflux, reflux is established only during placement of the filter distal to plaque P within the ICA. Reflux is then stopped while the interventional procedure is performed on the plaque P. The reflux is then re-established while the filter is removed. In another embodiment, the filter is placed within the ICA distal to the plaque P and backflow is established while the filter is in place. This embodiment combines the use of a distal filter with backflow.

Although various method and apparatus embodiments are described in detail herein with reference to several types, it is recognized that other types, implementations, methods of use, and combinations thereof are also possible. It should be. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
The disclosure herein may include the following aspects.
(Aspect 1)
A transcervical access device that:
an arterial access sheath having a sheath body defining an internal lumen, the sheath body being sized and shaped to be introduced into a common carotid artery and to receive blood flow from the artery;
an elongate tube attached to a proximal end of the sheath body, wherein a connector connects the tube with the sheath body;
an adapter at the proximal end of the elongate tube, the adapter having a hub adapted to removably connect with a blood flow shunt line, the adapter connecting to an internal lumen of a transcervical access device; an adapter further comprising a valve disposed proximately, the valve controlling flow from the internal lumen of the transcervical access device toward the hub;
a proximal extension connected to the proximal end of the adapter, the proximal extension being formed from an elongated body;
a hemostatic valve at the proximal end of the proximal extension such that the proximal extension positions the hemostasis valve away from the adapter; and
A transcervical access device including a flush line connected to the proximal end of the proximal extension and providing a fluid passageway within the sheath body for flushing.
(Aspect 2)
5. The transcervical access device of embodiment 1, further comprising an eyelet located on a connector connecting the elongated tube to an adapter.
(Aspect 3)
Aspect 1, wherein the valve transitions between an open state that allows blood flow from the internal lumen of the transcervical access device and a closed state that blocks blood flow from the internal lumen of the transcervical access device. The transcervical access device described.
(Aspect 4)
further comprising a sheath stopper positionable on the sheath body to cover a portion of the sheath body and expose a portion of the sheath body, the sheath stopper being positioned within the carotid artery to expose a distal portion of the sheath body. The transcervical access device of aspect 1, wherein the flange is located at the distal end of the sheath stopper.
(Aspect 5)
5. The transcervical access device of aspect 4, wherein the flange is inflatable or mechanically expandable.
(Aspect 6)
A transcervical access device that:
an arterial access sheath having a sheath body defining an internal lumen, the sheath body being sized and shaped to be introduced into a common carotid artery and to receive blood flow from the artery;
an adapter at the proximal end of the sheath body, the adapter having a hub adapted to removably connect with a blood flow shunt line, the adapter proximate the internal lumen of the transcervical access device; an adapter further comprising a valve disposed as a hub, the valve controlling flow from the internal lumen of the transcervical access device toward the hub;
a proximal extension connected to the proximal end of the adapter, the proximal extension being formed from an elongate body;
a hemostatic valve at the proximal end of the proximal extension such that the proximal extension positions the hemostasis valve away from the adapter; and
A transcervical access device including a flush line connected to the proximal end of the proximal extension and providing a fluid passageway within the sheath body for flushing.
(Aspect 7)
7. The transcervical access device of embodiment 6, further comprising an eyelet located on the connector connecting the sheath body to the adapter.
(Aspect 8)
Aspect 6, wherein the valve transitions between an open state that allows blood flow from the internal lumen of the transcervical access device and a closed state that blocks blood flow from the internal lumen of the transcervical access device. The transcervical access device described.
(Aspect 9)
further comprising a sheath stopper positionable on the sheath body to cover a portion of the sheath body and expose a portion of the sheath body, the sheath stopper being positioned within the carotid artery such that a distal portion of the sheath body is exposed. 7. The transcervical access device of aspect 6, wherein the flange is located at the distal end of the sheath stopper.
(Aspect 10)
further comprising a blood flow shunt line removably connected to the hub of the adapter, further comprising a single housing on the blood flow shunt line, the housing:
a blood flow control element capable of moving between low and high flow states of blood flow through the blood flow shunt;
a valve capable of transitioning between an open state that allows blood flow through the blood flow shunt and a closed state that blocks blood flow through the blood flow shunt;
fluid filter; and
7. A transcervical access device according to aspect 1 or 6, comprising a one-way check valve.
(Aspect 11)
11. The apparatus of aspect 10, wherein the blood flow shunt line switches flow from the access device to the return site.

Claims (9)

an access sheath having a sheath body defining an internal lumen, the sheath body being sized and shaped to be introduced into a carotid artery and to receive blood flow from the carotid artery ;
an adapter at the proximal end of the sheath body, the adapter having a hub adapted to removably connect with a blood flow shunt line, the adapter proximate the internal lumen of the access device; an adapter further comprising a valve disposed at the inner lumen of the access device, the valve controlling flow from the inner lumen of the access device toward the hub;
a proximal extension connected to the proximal end of the adapter, the proximal extension being formed from an elongated body;
a hemostatic valve at the proximal end of the proximal extension, such that the proximal extension positions the hemostasis valve away from the adapter; and a portion of the sheath body that covers and covers a portion of the sheath body. a sheath stopper positionable on the sheath body to expose the sheath body, the sheath stopper restricting insertion of the sheath body into the carotid artery to an exposed distal portion of the sheath body; A device for accessing the cerebral vasculature via the carotid artery , disposed at the distal end of the sheath stopper. an access sheath having a sheath body defining an internal lumen, the sheath body being sized and shaped to be introduced into a carotid artery and to receive blood flow from the carotid artery;
an elongate tube attached to a proximal end of the sheath body, wherein a connector connects the tube with the sheath body;
an adapter at the proximal end of the elongated tube, the adapter having a hub adapted to removably connect with a blood flow shunt line, the adapter proximate an internal lumen of the access device; an adapter further comprising a valve disposed at the inner lumen of the access device, the valve controlling flow from the inner lumen of the access device toward the hub;
a proximal extension connected to the proximal end of the adapter, the proximal extension being formed from an elongated body;
a hemostatic valve at the proximal end of the proximal extension, such that the proximal extension positions the hemostasis valve away from the adapter; and
a sheath stopper disposed on the sheath body to cover a portion of the sheath body and expose a portion of the sheath body; the sheath stopper prevents insertion of the sheath body into the carotid artery; A device for accessing the cerebral vasculature via the carotid artery, restricted to an exposed distal portion of the sheath body, the flange being disposed at the distal end of the sheath stopper. 3. The device of claim 2, further comprising an eyelet located on a connector connecting the elongated tube to the adapter. 2. The device of claim 1, further comprising an eyelet located on a connector connecting the sheath body to the adapter. The valve is configured to transition between an open state that allows blood flow from the internal lumen of the device and a closed state that blocks blood flow from the internal lumen of the device. 3. The device according to claim 1 or 2 . 3. A device according to claim 1 or 2 , wherein the flange is inflatable or mechanically expandable. further comprising a blood flow shunt line removably connectable to the hub of the adapter, further comprising a single housing on the blood flow shunt line, the housing:
a blood flow control element capable of moving between a low flow state and a high flow state of blood flow through the blood flow shunt line;
a valve that is transitionable between an open state that allows blood flow through the blood flow shunt line and a closed state that blocks blood flow through the blood flow shunt line;
3. The device of claim 1 or 2 , further comprising: a fluid filter; and a one-way check valve. 8. The device of claim 7, wherein the blood flow shunt line is configured to switch flow from the access device to a return site. 3. The device of claim 1 or 2 , wherein the sheath body includes a reduced diameter distal region.

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